TY - JOUR
T1 - Synaptic and epidermal accumulations of human acetylcholinesterase are encoded by alternative 3'-terminal exons
AU - Seidman, S.
AU - Sternfeld, M.
AU - Aziz-Aloya, R. B.
AU - Timberg, R.
AU - Kaufer-Nachum, D.
AU - Soreq, H.
PY - 1995
Y1 - 1995
N2 - Tissue-specific heterogeneity among mammalian acetylcholinesterases (ACHE) has been associated with 3' alternative splicing of the primary AChE gene transcript. We have previously demonstrated that human AChE DNA encoding the brain and muscle AChE form and bearing the 3' exon E6 (ACHE-E6) induces accumulation of catalytically active AChE in myotomes and neuromuscular junctions (NMJs) of 2- and 3-day-old Xenopus embryos. Here, we explore the possibility that the 3'-terminal exons of two alternative human AChE cDNA constructs include evolutionarily conserved tissue-recognizable elements. To this end, DNAs encoding alternative human AChE mRNAs were microinjected into cleaving embryos of Xenopus laevis. In contrast to the myotomal expression demonstrated by ACHE-E6, DNA carrying intron 14 and alternative exon E5 (ACHE-14/E5) promoted punctuated staining of epidermal cells and secretion of AChE into the external medium. Moreover, ACHE-E6-injected embryos displayed enhanced NMJ development, whereas ACHE-14/E5-derived enzyme was conspicuously absent from muscles and NMJs and its expression in embryos had no apparent effect on NMJ development. In addition, cell-associated AChE from embryos injected with ACHE-14/E5 DNA was biochemically distinct from that encoded by the muscle-expressible ACHE-E6, displaying higher electrophoretic mobility and greater solubility in low-salt buffer. These findings suggest that alternative 3'-terminal exons dictate tissue-specific accumulation and a particular biological role(s) of ACHE, associate the 3' exon E6 with NMJ development, and indicate the existence of a putative secretory AChE form derived from the alternative 14/E5 AChE mRNA.
AB - Tissue-specific heterogeneity among mammalian acetylcholinesterases (ACHE) has been associated with 3' alternative splicing of the primary AChE gene transcript. We have previously demonstrated that human AChE DNA encoding the brain and muscle AChE form and bearing the 3' exon E6 (ACHE-E6) induces accumulation of catalytically active AChE in myotomes and neuromuscular junctions (NMJs) of 2- and 3-day-old Xenopus embryos. Here, we explore the possibility that the 3'-terminal exons of two alternative human AChE cDNA constructs include evolutionarily conserved tissue-recognizable elements. To this end, DNAs encoding alternative human AChE mRNAs were microinjected into cleaving embryos of Xenopus laevis. In contrast to the myotomal expression demonstrated by ACHE-E6, DNA carrying intron 14 and alternative exon E5 (ACHE-14/E5) promoted punctuated staining of epidermal cells and secretion of AChE into the external medium. Moreover, ACHE-E6-injected embryos displayed enhanced NMJ development, whereas ACHE-14/E5-derived enzyme was conspicuously absent from muscles and NMJs and its expression in embryos had no apparent effect on NMJ development. In addition, cell-associated AChE from embryos injected with ACHE-14/E5 DNA was biochemically distinct from that encoded by the muscle-expressible ACHE-E6, displaying higher electrophoretic mobility and greater solubility in low-salt buffer. These findings suggest that alternative 3'-terminal exons dictate tissue-specific accumulation and a particular biological role(s) of ACHE, associate the 3' exon E6 with NMJ development, and indicate the existence of a putative secretory AChE form derived from the alternative 14/E5 AChE mRNA.
UR - http://www.scopus.com/inward/record.url?scp=0029004391&partnerID=8YFLogxK
U2 - 10.1128/MCB.15.6.2993
DO - 10.1128/MCB.15.6.2993
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 7760797
AN - SCOPUS:0029004391
SN - 0270-7306
VL - 15
SP - 2993
EP - 3002
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
IS - 6
ER -