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What does acetylcholinesterase do in hematopoietic cells?

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Gene Therapy and Molecular Biology Vol 3, page 347

Gene Ther Mol Biol Vol 3, 347-354. August 1999.

What does acetylcholinesterase do in hematopoietic cells?

Review Article

Roxanne Y.Y. Chan and Bernard J. Jasmin*

Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5

*Correspondence: Bernard.J. Jasmin, Ph.D., Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5. Tel: (613) 562-5800 ext: 8383; Fax: (613) 562-5434; E-mail: bjasmin@danis.med.uottawa.ca

Key words : acetylcholinesterase, cholinergic synapses, hematopoietic cells, tumor suppressor, myeloid leukaemia, apoptosis, proliferative disorders

Abbreviations : AchE , acetylcholinesterase; GPI , glycosyl-phosphatidylinositol; PI-PLC, phosphatidylinositol-specific phospholipase C

Received: 19 November 1998; accepted: 10 December 1998

Summary

Acetylcholinesterase (AChE) is an essential component of cholinergic synapses since it hydrolyzes acetylcholine released from presynaptic nerve terminals. However, it is well documented that AChE is also expressed in a variety of non-cholinergic tissues including hematopoietic cells. Despite the recent progress made in our understanding of the molecular mechanisms regulating expression of AChE, our knowledge of the precise function of this enzyme in hematopoietic cells still remains limited. Previous work has led to the notion that AChE may be involved in myelodysplastic syndromes as well as acute myeloid leukaemias since it may regulate hematopoiesis by acting as a tumor suppressor gene. In addition, recent studies have further demonstrated the involvement of AChE in the proliferation of multipotent stem cells, as well as in the mechanisms leading to apoptosis in cells undergoing erythroid and megakaryocytic differentiation. In this review, we first present an overview of the cellular and molecular biology of AChE and then, focus more specifically on the expression of AChE in hematopoietic cells. Finally, we also discuss the recent evidence linking AChE expression and the proliferative capacity of these cells. A better understanding of the functional significance of AChE in hematopoietic cells may be relevant for the future design of novel therapeutic strategies against proliferative disorders of hematopoietic tissues.

I. Introduction

Acetylcholinesterase (AChE; EC 3.1.1.7) is an essential component of cholinergic synapses in both central and peripheral nervous systems. Within these specialized structures, AChE is responsible for the rapid hydrolysis of acetylcholine released from presynaptic nerve terminals thereby ensuring precise temporal control of synaptic transmission (see for review Massoulié et al., 1993; Taylor and Radic, 1994). However, it is well documented that AChE is also expressed in a variety of non-cholinergic tissues. For example, non-cholinergic regions of the brain such as the
hippocampus and cerebellum express large amounts of AChE (see for example Landwehrmeyer et al., 1993; Legay et al.,
1993a; Hammond et al., 1994 and refs therein). Furthermore, AChE has been shown to be homologous to the cell adhesion molecules glutactin and neurotactin (Krejci et al.,
1991) as well as to neuroligins which are neuronal cell surface proteins (Ichtchenko et al., 1996). Such findings have led to the suggestion that AChE may perform additional, non-classical function in the nervous system (Robertson and Yu, 1993; Greenfield, 1995; Layer and Willbold, 1995).
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Figure 1. Quaternary structures of AChE molecular forms. Homomeric forms consist of monomer G1 , dimer G2 , tetramer G4 and a glycophospholipid (GPI)-linked dimer. Heteromeric forms consist of the hydrophobic-tailed G4 form and the asymmetric forms containing a collagenic structural subunit. Only the asymmetric form A12

is shown.

Interestingly, AChE is also abundantly expressed in hematopoietic cells where its expression is even more puzzling. Although the presence of AChE in erythrocytes was detected more than 70 years ago (see Lawson and Barr,
1987), its role in blood cell physiology still remains unclear. In recent years however, there has been considerable interest in this issue, and there is now increasing evidence suggesting the existence of a link between AChE expression and the proliferation and differentiation of hematopoietic cells. In this brief review, we initially describe the cellular and molecular biology of AChE and then focus more specifically on the putative involvement of this enzyme in the development of blood cells and elements. Our main objective is to highlight some of the latest findings which should prove useful to design further experimentation dealing with the regulation and functional significance of AChE during hematopoiesis under normal and pathological conditions.

II.The AChE molecular forms and splice variants

AChE exists as a family of molecular forms which differ in their structures and hydrodynamic characteristics while displaying similar catalytic properties (Taylor, 1991; see Massoulié et al., 1993). The molecular forms may be classified as homomeric or heteromeric on the basis of their association with specialized structural subunits (Figure 1 ).
Homomeric forms include monomer G1, dimer G2 and tetramer G4 as well as a glycophospholipid-linked (GPI) dimer. Heteromers on the other hand, consist of: (i ) amphiphilic tetramers G4 linked to a 20 kDa hydrophobic anchor; and (ii ) the asymmetric forms A4, A8 or A12 in which 1, 2 or 3 soluble tetramers attach to a collagenic subunit, respectively. The functional significance of such polymorphism remains to be established yet, it has been proposed that it allows the placement of AChE molecules at distinct cellular locations where they can assume site-specific functions.
Previous studies have shown that AChE is encoded by a single gene (Rotundo et al., 1988; Maulet et al., 1990; Soreq et al., 1990; Li et al., 1993a; Chan and Jasmin, 1995). Although only one copy of the gene exists, several transcripts are produced by alternative splicing (Sikorav et al., 1987, 1988; Schumacher et al., 1988; Maulet et al.,
1990) (Figure 2 ). In mammals, exon 1 is untranslated while exons 2, 3 and part of exon 4 appear in all AChE transcripts since they encode the common catalytic domain of the mature protein (Li et al., 1991, 1993a). The C-terminal region of the protein is variable and is encoded either by the rest of exon 4 (called R for readthrough), or by alternatively spliced exons 5 or 6 to yield the H (hydrophobic) or T (tail) transcript, respectively. Two polyadenylation signals have been identified which in the case of the T transcript for
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example, give rise to two mRNAs of 2.4 and 3.2 kb
(Rachinsky et al., 1990; Legay et al., 1993a).
The H transcript encodes the AChE catalytic subunit that contains the signal for GPI addition (Li et al., 1991) which ultimately leads to the formation of GPI-linked dimers (Li et al., 1991; Legay et al., 1993b; Michaelson et al., 1994; Coussen et al., 1995). This GPI-linked AChE dimer is expressed in mature erythrocytes and T lymphocytes (Ott et al., 1982; Szelenyi et al., 1982; Rosenberry and Scoggin,
1984; Roberts et al., 1987). By contrast, the T transcript can give rise to all other AChE molecular forms when co- expressed with appropriate structural subunits (Duval et al.,
1992). The T transcript is abundantly expressed in muscle and neuron where it accounts therefore, for the multiplicity of molecular forms found in these cell types (Li et al., 1991; Duval et al., 1992; Li et al., 1993a; Legay et al., 1993a). Finally, the R transcript encodes a secreted AChE monomer whose expression may be developmentally regulated (Li et al., 1993b; Legay et al., 1995; Chan et al., 1998).

III. Expression of AChE in hematopoietic cells

Previous studies have shown that T lymphocytes (Szelenyi et al., 1982), platelets (Schukla, 1986; Koekebakker and Barr, 1988; Sánchez-Yagüe et al., 1990) and erythrocytes (Low and Finean, 1977; Massoulié and Bon,
1982; Toutant et al., 1989) express significant levels of AChE. Interestingly, there are notable differences between species concerning the distribution of the enzyme in blood cell lineages. Biochemical analysis of AChE in erythrocytes has shown that humans have the highest levels of enzyme activity while cats have none (Zajicek, 1957). However, platelets and megakaryocytes from cats contain large amounts of AChE whereas in humans, these cells express only low levels of enzyme activity. Other species such as guinea pigs, horses, rabbits, and rodents, fall in between these two extremes, but AChE activity tends to typically be found predominantly in one cell lineage (Zajicek, 1957). The significance of this variability between species and cell types remains currently unclear.
Amongst blood cell lineages, erythrocytes have been the most thoroughly studied in terms of AChE expression. Mammalian erythrocytes express GPI-linked AChE dimers on the extracellular surface of their plasma membrane (Ott et al., 1982; Rosenberry and Scoggin, 1984) and it has been shown that the GPI moiety is particularly important for anchoring AChE molecules onto the cell membrane (Incardona and Rosenberry, 1996). Interestingly, a certain degree of variation has been observed in the structure of the inositol ring within the glycolipid anchor. For example, AChE has been shown to be released readily by phosphatidylinositol-specific phospholipase C (PI-PLC) in
porcine, bovine and rat erythrocytes, but not from human or murine erythrocytes. The presence of an additional acyl chain on the inositol ring in the latter two species is thought to confer the resistance of the GPI-linked AChE dimer to PI- PLC treatment (Roberts et al., 1988a,b). Such addition effectively prevents the formation of a cyclic myo-inositol
1:2-monophosphate which is an intermediate product of the PI-PLC cleavage reaction (Wilson et al., 1985). Consequently, deacylation of AChE in human and murine erythrocytes by alkaline hydroxylamine treatment renders the enzyme susceptible again to cleavage by PI-PLC (Toutant et al., 1989; 1991). By contrast to the information already available on the expression of AChE in erythrocytes, only a few studies have examined AChE in lymphocytes and platelets most likely because of their limited quantities in circulating blood (Méflah et al., 1984; Bartha et al., 1987; Richier et al., 1992).
Histochemical studies of early hematopoietic cells have revealed that AChE is present in several distinct subcellular compartments. In human bone marrow cultures, AChE is detected in both the nucleus and cytoplasm of erythroblasts (Koekebakker and Barr, 1988), as well as in the nucleus of immature megakaryocytes (Lev-Lehman et al., 1997). A close examination of AChE expression during murine erythroid cell maturation further indicates that the enzyme is widely distributed in the nuclear membrane, endoplasmic reticulum and Golgi apparatus at early stages of development, and that it becomes confined to the Golgi apparatus in orthochromatic nucleated red blood cells in accordance with the end of AChE biosynthesis at this particular stage of cellular differentiation (Keyhani and Maigne, 1981). In addition, it appears that AChE is also secreted from normoblasts (Keyhani and Maigne, 1981) and megakaryocytes (Paulus et al., 1981). Taken together, these results suggest that the subcellular distribution of AChE as well as the species of molecular forms that are expressed, vary with the stage of hematopoietic cell differentiation. Accordingly, these changes in AChE localization and expression may therefore reflect distinct roles for the different molecular forms at specific stages of cell maturation (see Chan et al., 1998).
Previous studies have also determined the species of mRNAs expressed in various hematopoietic tissues. Analysis of rat fetal liver and spleen has shown for example that all three splice variants are present in these hematopoietic organs (Legay et al., 1993b). Studies using adult mouse bone marrow (Li et al., 1993a) and murine erythroleukemia (MEL) cells (Chan et al., 1998) have also revealed a similar pattern of expression thereby suggesting that hematopoietic cells from both embryonic and adult tissues are capable of expressing, albeit at different levels, the R, H and T transcripts of AChE.
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Figure 2. Structure of the mammalian AChE gene and alternative splicing of AChE mRNAs. The promoter (P), exons (dark boxes), introns (light boxes) and 3'UTR (hatched box) containing two polyA+ signals (A) are shown. 4' denotes part of exon 4 that is retained together with intron 4 in the splicing of the R transcript. Note that splicing from exon 4 to either exon 5 or 6 generate the H and T transcripts, respectively.

Since in our recent studies we have observed a preponderance of R and T transcripts in MEL cells (Chan et al., 1998; see also Li et al., 1993a) which basically correspond to erythroblasts and normoblasts (Friend et al.,
1971), and since mature hematopoietic cells express significant amounts of GPI-linked dimers that are encoded by the H transcript (see Figure 2 ), it may thus be hypothesized that the splicing pattern of immature AChE mRNA changes during differentiation of hematopoietic cells hence, further supporting the notion that different AChE molecular forms, originating from different transcripts (see above), are required at distinct stages of hematopoiesis (Chan et al., 1998).

IV. Function of AChE in hematopoietic cells

The hypothesis that AChE is involved in physiological functions other than the termination of neurotransmission has received considerable attention particularly in the nervous system where these putative additional roles are collectively referred to as the non-cholinergic functions of AChE (Robertson and Yu, 1993; Greenfield, 1995; Layer and
Willbold, 1995). In this context, there has been an increasing number of reports that have recently demonstrated that AChE can in fact regulate neuronal morphogenesis and differentiation independently of its catalytic activity (see for example Layer et al., 1993; Jones et al., 1995; Small et al.,
1995, Dupree and Bigbee, 1996; Inestrosa et al., 1996; Beeri et al., 1997; Holmes et al., 1997; Koenigsberger et al.,
1997; Robitzki et al., 1997; Srivatsan and Peretz, 1997; Sternfeld et al., 1998).
In hematopoietic cells, the presence of AChE remains an enigma but there is nonetheless, considerable interest in identifying the physiological role of AChE in these cells particularly since the AChE gene maps to 7q22 (Getman et al., 1992) which is considered a critical region of the genome involved in the development of myelodysplastic syndromes and acute myeloid leukemias (Kere et al., 1989; Baranger et al., 1990; Mufti, 1992; Green, 1993). Additional clinical observations have further supported a link between aberrations in the AChE gene and severe hematological disorders. For example, the AChE gene frequently undergoes incomplete somatic amplification (Lapidot-Lifson et al.,
1989) and mutation (Zakut et al., 1992) in hematological proliferation disorders such as megakaryocytopoiesis and
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thrombopoiesis. Furthermore, organophosphates, which are potent inhibitors of AChE and key components of pesticides, are believed to represent causative agents in various forms of leukemias (Brown et al., 1990). Although the role of AChE in hematopoietic cells is still unclear, the location of the AChE gene in a region which may contain a novel myeloid- specific tumor suppressor gene (Le Beau et al., 1986; Neuman et al., 1992; Johansson et al., 1993; Rodrigues et al., 1996; Le Beau et al., 1996), has led to the suggestion that AChE may in fact function as a tumor suppressor by regulating proliferation, differentiation and apoptotic events during normal hematopoietic cell development (Soreq et al.,
1994; Stephenson et al., 1996).
Over the last two decades, several laboratories have directly examined the role of AChE in hematopoietic cells by using distinct experimental approaches. Treatment of mice with the AChE inhibitor neostigmine, resulted in significant increases in colony forming unit-megakaryocytes in the humerus as well as in the percentage of progenitor cells undergoing DNA synthesis (Burnstein et al., 1980). Similarly, suppression of AChE expression using sequence- specific antisense oligonucleotides in cultures from mouse bone marrow cells led to enhanced proliferation of pluripotent stem cells committed to erythropoiesis, megakaryocytopoiesis and macrophage production (Soreq et al., 1994). Interestingly, and of particular relevance, normal apoptosis in these cells was significantly reduced in comparison to untreated cell cultures (Soreq et al., 1994). Based on these latter studies, it appears therefore that the functional role of AChE is to limit the proliferation of hematopoietic stem cells since its function is expected to be inversely related to the effects of the AChE antisense oligonucleotides.
Additional studies performed by other laboratories including ours, have also examined the relationship that appears to exist between AChE and the proliferative capacity of hematopoietic cells. Using MEL cells in culture for example, we have demonstrated a large increase in both intracellular and secreted AChE activity during cellular differentiation which coincides with hemoglobinization and the concomitant loss of their proliferative capacity (Chan et al., 1998). Paoletti and co-workers have found that fast- growing MEL cell clones express consistently lower levels of AChE enzyme activity as compared to slow-growing ones (Paoletti et al., 1992). In addition, treatment of these cells with exogenous AChE has been shown to lead to a marked decrease in cell growth (Paoletti et al., 1992). In our experiments, we have also recently observed following AChE addition to the growth media, significantly more cell death in MEL cells already committed to the differentiation program most likely as a result of apoptotic events (unpublished observation). Together these results suggest therefore that AChE can act as a negative regulator of cellular replication along the differentiation program of
hematopoietic stem cells. Further confirmation of the role of AChE in regulating apoptosis in these cells may lead to the identification of additional regulatory mechanisms controlling programmed cell death in hematopoietic tissues and that the loss of this regulatory step may in fact be involved in the etiology of hematological disorders including leukemias.

V. Conclusions and perspectives

The notion that AChE fulfils additional, non-cholinergic functions has received an increasing amount of attention. In this context, hematopoietic cells are of considerable interest since there is now ample evidence showing that AChE is expressed both in early hematopoietic progenitors as well as in mature blood cells and elements. Although the specific function of AChE in hematopoietic cells remains obscure, converging lines of evidence suggest the existence of a link between AChE levels and the proliferative capacity of these cells. Future experiments will therefore prove useful not only to further test this hypothesis directly, but also, to begin delineating the splice variants, the regions of the AChE molecule as well as the signal transduction pathways that may be involved in mediating these effects. Because of the postulated clinical relationship between AChE expression and hematological disorders, it may also be envisaged that studies focusing on the regulation and functional significance of AChE expression in hematopoietic cells may ultimately lead to the design of novel therapeutic strategies.

Acknowledgement

The financial support of the Medical Research Council of Canada and of the Faculty of Medicine, University of Ottawa, is gratefully acknowledged. We also wish to thank members of the Jasmin laboratory for fruitful discussion.

References

Baranger L, Baruchel A, Leverger G, Schaison G, Berger R. (1990 ) Monosomy-7 in childhood hemopoietic disorders. Leukemia 4, 345-347

Bartha E, Rakonczay Z, Kása P, Hollán S, Gyévai A. ( 1987 ) Molecular form of human lymphocyte membrane-bound acetylcholinesterase. Life Sci 41, 1853-1860

Beeri R, Le Novere N, Mervis R, Huberman T, Grauer E, Changeux JP, Soreq H. (1997 ) Enhanced hemicholinium binding and attenuated dendrite branching in cognitively impaired acetylcholinesterase-transgenic mice. J Neurochem 69, 2441-2451

Brown LM, Blair A, Gibson R, Everett GD, Cantor KP, Schulman LM, Burmeister LF, Van Lier SF, Dick F. (1990 ) Pesticide exposures and other agricultural risk factors for leukemia among men in Iowa and Minnesota. Cancer Res 50, 6585-

6591

351

Chan and Jasmin: Acetylcholinesterase in hematopoietic cells

Burstein SA, Adamson JW, Harker LA. (1980 ) Megakaryocytopoiesis in culture: modulation by cholinergic mechanisms. J Cell Physiol 103, 201-208

Chan RYY, Jasmin BJ. (1995 ) Regulatory elements and transcription of the acetylcholinesterase gene in adult rat skeletal muscle fibers. Soc for Neurosci 21, 800 (abstr.)

Chan RYY, Adatia FA, Krupa AM, Jasmin BJ. (1998 ) Increased expression of acetylcholinesterase T and R transcripts during hematopoietic differentiation is accompanied by parallel elevations in the levels of their respective molecular forms. J Biol Chem 273, 9727-9733

Coussen F, Bonnerot C, Massoulié‚ J. (1995 ) Stable expression of acetylcholinesterase and associated collagenic subunits in transfected RBL cell lines: production of GPI- anchored dimers and collagen-tailed forms. Eur J Cell Biol 67, 254-260

Dupree JL, Bigbee JW. (1996 ) Acetylcholinesterase inhibitor treatment delays recovery from axotomy in cultured dorsal root ganglion neurons. J Neurocytol 25, 439-454

Duval N, Massoulié J, Bon S. (1992 ) H and T subunits of acetylcholinesterase from Torpedo, expressed in COS cells, generate all types of globular forms. J Cell Biol 118,

641-653

Friend C, Scher W, Holland JG, Sato T. (1971 ) Hemoglobin synthesis in murine erythroleukemia cells in vitro: stimulation of erythroid differentiation by dimethylsulfoxide. Proc Natl Acad Sci USA 68, 378-

382

Getman DK, Eubanks JH, Camp S, Evans GA, Taylor P. (1992 ) The human gene encoding acetylcholinesterase is located on the long arm of chromosome 7. Am J Hum Genet 51,

170-177

Green AR. (1993 ) Chromosomal deletions in haematological malignancies. Lancet 341, 1567-1568

Greenfield SA. (1995 ) A non-cholinergic function for acetylcholinesterase. In: DM Quinn, AS Balasubramanian, BP Doctor, P Taylor (eds). Enzymes of the Cholinesterase Family, New York: Plenum Press, 415-421

Hammond R, Rao R, Koenigsberger C, Brimijoin S. (1994 ) Regional variation in expression of acetylcholinesterase mRNA in adult rat brain analyzed by in situ hybridization. Proc Natl Acad Sci USA 91, 10933-10937

Holmes C, Jones SA, Budd TC, Greenfield SA. (1997 ) Non- cholinergic, trophic action of recombinant acetylcholinesterase on mid-brain dopaminergic neurons. J Neurosci Res 49, 207-218

Ichtchenko K, Nguyen T, Südhof TC. (1996 ) Structures, alternative splicing, and neurexin binding of multiple neuroligins. J Biol Chem 271, 2676-2682

Incardona JP, Rosenberry TL. (1996 ) Construction and characterization of secreted and chimeric transmembrane forms of Drosophila acetylcholinesterase: a large truncation of the c-terminal signal peptide does not eliminate glycoinositol phospholipid anchoring. Mol Biol Cell 7,

595-611

Inestrosa NC, Alvarez A, Calderon F. (1996 ) Acetylcholinesterase is a senile plaque component that promotes assembly of amyloid beta-peptide into Alzheimer's filaments. Mol Psychiatry 1, 359-361

Johansson B, Mertens F, Mitelman F. (1993 ) Cytogenetic deletion maps of hematologic neoplasms:Circumstantial evidence for tumor suppressor loci. Genes Chrom Cancer 8, 205-218

Jones SA, Holmes C, Budd TC, Greenfield SA. (1995 ) The effect of acetylcholinesterase on outgrowth of dopaminergic neurons in organotypic slice culture of rat midbrain. Cell Tissue Res 279, 323-330

Kere J, Ruutu T, Davies KA, Robinson IB, Watkins PC, Winqvist R, Chapelle A de la. (1989 ) Chromosome 7 long arm deletion in myeloid disorders: a narrow breakpoint region in

7q22 defined by molecular mapping. Blood 73, 230-234

Keyhani E, Maigne J. (1981 ) Acetylcholinesterase in mammalian erythroid cells. J Cell Sci 52, 327-339

Koekebakker M, Barr RD. (1988 ) Acetylcholinesterase in the human erythron. I. Cytochemistry. Am J Hematol 28,

252-259

Koenigsberger C, Chiappa S, Brimijoin S (1997 ) Neurite differentiation is modulated in neuroblastoma cells engineered for altered acetylcholinesterase expression. J Neurochem 69, 1389-1397

Krejci E, Duval N, Chatonnet A, Vincens P, Massoulié J. (1991 ) Cholinesterase-like domains in enzymes and structural proteins: functional and evolutionary relationships and identification of a catalytically essential aspartic acid. Proc Natl Acad Sci USA 88, 6647-6651

Landwehrmeyer B, Probst A, Palacios JM, Mengod G. (1993 ) Expression of acetylcholinesterase messenger RNA in human brain: an in situ hybridization study. Neurosci 57,

615-634

Lapidot-Lifson Y, Prody CA, Ginzberg D, Meytes D, Zakut H, Soreq H. (1989 ) Coamplification of human acetylcholinesterase and butrylcholinesterase genes in blood cells: correlation with various leukemias and abnormal megakaryocytopoiesis. Proc Natl Acad Sci USA 86, 4715-4717

Lawson AA, Barr RD. (1987 ) Acetylcholinesterase in red blood cells. Am J Haematol 26, 101-112

Layer PG, Weikert T, Alber R. (1993 ) Cholinesterase regulate neurite growth in chick nerve cells in vitro by means of a non-enzymatic mechanism. Cell Tissue Res 273, 219-

226

Layer PG, Willbold E. (1995 ) Novel functions of cholinesterases in development, physiology and disease. Prog Histochem Cytochem 29, 1-99

Le Beau MM, Albain KS, Larson RA, Vardiman JW, Davis EM, Blough RR, Golomb HM, Rowley JD. (1986 ) Clinical and cytogenetic correlations in 63 patients with therapy-related myelodysplastic syndromes and acute nonlymphocytic leukemia: Further evidence for characteristic abnormalities of chromosomes nos. 5 and 7. J Clin Oncol 3, 325-345

352

Gene Therapy and Molecular Biology Vol 3, page 353

Le Beau MM, Espinosa R III, Davis EM, Eisenbart JD, Larson AA, Green ED. (1996 ) Cytogenetic and molecular delineation of a region of chromosome 7 commonly deleted in malignant myeloid diseases. Blood 88, 1930-1953

Legay C, Bon S, Vernier P, Coussen F, Massoulié J. (1993a ) Cloning and expression of a rat acetylcholinesterase subunit: generation of multiple molecular forms and complementarity with a Torpedo collagenic subunit. J Neurochem 60, 337-346

Legay C, Bon S, Massoulié J. (1993b ) Expression of a cDNA encoding the glycolipid-anchored form of rat acetylcholinesterase. FEBS Lett 31, 163-166

Legay C, Huchet M, Massoulié J, Changeux J-P. (1995 ) Developmental regulation of acetylcholinesterase transcripts in the mouse diaphragm: Alternative splicing and focalization. Eur J Neurosci 7, 1803-1809

Lev-Lehman E, Deutsch V, Eldor A, Soreq H. (1997 ) Immature human megakaryocytes produce nuclear-associated acetylcholinesterase. Blood 89, 3644-3653

Li Y, Camp S, Rachinsky TL, Getman D, Taylor P. (1991 ) Gene structure of mammalian acetylcholinesterase. Alternative exons dictate tissue-specific expression. J Biol Chem

266, 23083- 23090

Li Y, Camp S, Taylor P. (1993a ) Tissue-specific expression and alternative mRNA processing of the mammalian acetylcholinesterase gene. J Biol Chem 268, 5790-5797

Li Y, Camp S, Rachinsky TL, Bongiorno C, Taylor P. (1993b ) Promoter elements and Transcriptional control of the mouse acetylcholinesterase gene. J Biol Chem 268, 3563-3572

Low MG, Finean JB. (1977 ) Non-lytic release of acetylcholinesterase from erythrocytes by a phosphatidylinositol-specific phospholipase C. FEBS Lett 82, 143-146

Massoulié J, Bon S. (1982 ) The molecular forms of cholinesterase and acetylcholinesterase in vertebrates. Ann Rev Neurosci 5, 57-106

Massoulié J, Pezzementi L, Bon S, Krejci E, Vallette FM. (1993 ) Molecular and cellular biology of cholinesterases. Prog Neurobiol 13, 31-91

Maulet Y, Camp S, Gibney G, Rachinski T, Ekstrom TJ, Taylor P. (1990 ) Single gene encodes glycophospholipid- anchored and asymmetric acetylcholinesterase forms: alternative coding exons contain inverted repeat sequences. Neuron 4, 289-301

Méflah K, Bernard S, Massoulié J. (1984 ) Interactions with lectins indicate differences in the carbohydrate composition of the membrane-bound enzymes acetylcholinesterase and

5'-nucleotidase in different cell types. Biochimie 66, 59-

69

Michaelson S, Small DH, Livett BG. (1994 ) Expression of dimeric and tetrameric acetylcholinesterase isoforms on the surface of cultured bovine adrenal chromaffin cells. J Cell Biochem 55, 398-407

Mufti GJ. (1992 ) Chromosomal deletions in the myelodysplastic syndrome. Leukemia Res 16, 35-41

Neuman WL, Rubin CM, Rios RB, Larson RA, Le Beau MM, Rowley JD, Vardiman JW, Schwartz JL, Farber R. (1992 ) Chromosomal loss and deletion are the most common mechanisms for loss of heterozygosity from chromosomes 5 and 7 in malignant myeloid disorders. Blood 79, 1501-

1510

Ott P, Lustig A, Brodbeck U, Rosenbusch JP. (1992 ) Acetylcholinesterase from human erythrocytes membranes: dimers as functional units. FEBS Lett 138, 187-189

Paoletti F, Mocali A, Vannucchi AM. (1992 ) Acetylcholinesterase in murine erythroleukemia (Friend) cells: evidence for megakaryocyte-like expression and potential growth-regulatory role of enzyme activity. Blood

79, 2873-2879

Paulus J-M, Maigne J, Keyhani E. (1981 ) Mouse megakaryocytes secrete acetylcholinesterase. Blood 58,

1100-1106

Rachinsky TL, Camp S, Li Y, Ekstrom TJ, Newton M, Taylor P. (1990 ) Molecular cloning of mouse acetylcholinesterase: tissue distribution of alternatively spliced mRNA species. Neuron 5, 317-327

Richier P, Arpagaus M, Toutant JP. (1992 ) Glycolipid-anchored acetylcholinesterases from rabbit lymphocytes and erythrocytes differ in their sensitivity to phosphatidylinositol-specific phospholipase C. Biochim Biophys Acta 1112, 83-88

Roberts WL, Kim BH, Rosenberry TL. (1987 ) Bovine brain acetylcholinesterase primary sequence involved in intersubunit disulfide linkages. Proc Natl Acad Sci USA

84, 7817-7821

Roberts WL, Myher JJ, Kuksis A, Low MG, Rosenberry TL. (1988a ) Structural characterization of the glycoinositol phospholipid membrane anchor of human erythrocyte acetylcholinesterase by fast atom bombardment mass spectrometry. J Biol Chem 263, 18766-18775

Roberts WL, Santikarn S, Reinhold VR, Rosenberry TL. (1988b ) Lipid analysis of the glycoinositol phospholipid membrane anchor of human erythrocyte acetylcholinesterase. J Biol Chem 263, 18776-18784

Robertson RT, Yu T. (1993 ) Acetylcholinesterase and neural development: new tricks for an old dog? News Physiol Sci 8, 266-268

Robitzki A, Mack A, Hoppe U, Chatonnet A, Layer PG. (1997 ) Regulation of cholinesterase gene expression affects neuronal differentiation as revealed by transfection studies on reaggregating embryonic chicken retinal cells. Eur J Neurosci 9, 2394-2405

Rodrigues Pereira Velloso E, Michaux L, Ferrant A, Hernandez M, Mesus P, Dierlamm J, Criel A, Louwagie A, Verhoef G, Booaerts M, Michaux JL, Bosly A, Mecucci C, Van den Berghe H. ( 1996 ) Deletions of the long arm of chromosome

7 in myeloid disorders: loss of band 7q32 implies worst prognosis. Br J Haematol 92, 574-581

Rosenberry TL, Scoggin DM. (1984 ) Structure of human erythrocyte acetylcholinesterase. Characterization of

353

Chan and Jasmin: Acetylcholinesterase in hematopoietic cells

intersubunit disulfide bonding and detergent interaction. J Biol Chem 259, 5643-5652

Rotundo RL, Gomez AM, Fernandez-Valle C, Randall WR. (1988 ) Allelic variants of acetylcholinesterase: genetic evidence that all acetylcholinesterase forms in avian nerves and muscles are encoded by a single gene. Proc Natl Acad Sci USA 85, 7805-7809

Sánchez-Yagüe J, Cabezas JA, Llanillo M. (1990 ) Subcellular distribution and characterization of acetylcholinesterase activities from sheep platelets: relationships between temperature-dependence and environment. Blood 76, 737-

744

Schukla SD. (1986 ) Action of phosphatidylinositol specific phospholipase C on platelets: nonlytic release of acetylcholinesterase, effect on thrombin and PAF induced aggregation. Life Sci 38, 751-755

Schumacher M, Maulet Y, Camp S, Taylor. (1988 ) Multiple mRNA species give rise to structural diversity in cholinesterase. J Biol Chem 263, 18979-18987

Sikorav JL, Krejci E, Massoulié J. (1987 ) cDNA sequences of Torpedo marmorata acetylcholinesterase: primary structure of the precursor of a catalytic subunit; existence of multiple

5' untranslated regions. EMBO J 6, 1865-1873

Sikorav JL, Duval N, Anselmet A, Bon S, Krejci E, Legay C, Osterlund M, Reimund B, Massouli‚ J. (1988 ) Complex alternative splicing of acetylcholinesterase in Torpedo electric organ. EMBO J 7, 2983-1873

Small DH, Gullveig R, Whitefield B, Nurcombe V. (1995 ) Cholinergic regulation of neurite outgrowth from isolated chick sympathetic neurons in culture. J Neurosci 15, 144-

151

Soreq H, Ben-Aziz R, Prody CA, Seidman S, Gnatt A, Neville L, Lieman-Hurwitz J, Lev-Lehman E, Ginzberg D, (1990 ) Lapidot-Lifson Y, Zakut H. Molecular cloning and construction of the coding region for human acetylcholinesterase reveals a G+C-rich attenuating structure. Proc Natl Acad Sci USA 87, 9688-9692

Soreq H, Patinkin D, Lev-Lehman E, Grifman M, Ginzberg D, Eckstein F, Zakut H. (1994 ) Antisense oligonucleotide inhibition of acetylcholinesterase gene expression induces progenitor cell expansion and suppresses hematopoietic apoptosis ex vivo. Proc Natl Acad Sci USA 91, 7907-

7911

Srivatsan M, Peretz B. (1997 ) Acetylcholinesterase promotes regeneration of neurites in cultured adult neurons of Aplysia. Neurosci 77, 921-931

Stephenson J, Czepulkowski B, Hirst W, Mufti GJ. (1996 ) Deletion of the acetylcholinesterase locus at 7q22 associated with myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). Leukemia Res 20, 235-241

Sternfeld M., Ming G-l, Song H-j, Sela K, Timberg R, Poo M-m, Soreq H. (1998 ) Acetylcholinesterase enhances neurite growth and synapse development through alternative contributions of its hydrolytic capacity, core protein, and variable c termini. J Neurosci 18, 1240-1249

Szelenyi JG, Bartha E, Hollan SR. (1982 ) Acetylcholinesterase activity of lymphocytes: an enzyme characteristic of T- cells. Brit J Haematol 50, 241-245

Taylor P. (1991 ) The cholinesterases. J Biol Chem 266,

4025-4028

Taylor P, Radic Z. (1994 ) The cholinesterases: from genes to proteins. Ann Rev Pharmacol Toxicol 34, 281-320

Toutant JP, Roberts WL, Murray NR, Rosenberry TL. (1989 ) Conversion of human erythrocyte acetylcholinesterase from an amphiphilic to a hydrophilic form by phosphatidylinositol-specific phospholipase c and serum phospholipase D. Eur J Biochem 180, 503-508

Toutant JP, Krall JA, Richards MK, Rosenberry TL. (1991 ) Rapid analysis of glycolipid anchors in amphiphilic dimers of acetylcholinesterases. Cell Biol Neurobiol 11, 219-

230

Wilson DB, Bross TE, Sherman WR, Berger RA, Majerus PW. (1985 ) Inositol cyclic phosphates are produced by cleavage of phosphatidylphosphoinositols (polyphosphoinositides) with purified sheep seminal vesicle phospholipase c enzymes. Proc Natl Acad Sci USA 82, 4013-4017

Zajicek J. (1957 ) Studies on the histogenesis of blood platelets megakaryocytes. Acta Physiol Scand 40, Suppl 138

Zakut H, Lapidot-Lifson Y, Beeri R, Ballin A, Soreq H. (1992 ) In vivo gene amplification in non-cancerous cells: cholinesterase genes and oncogenes amplify in thrombocytopenia associated with lupus erythematosus. Mutat Res 276, 275-284

354