title: Human choline acetyltransferase gene: localization of alternative first exons.
abstract: Two overlapping cosmids containing the 5' end of human choline acetyltransferase (ChAT) gene have been cloned. Using heterologous probes, we localized two alternative first exons homologous to rodent ChAT exons R and M (Misawa et al.: J Biol Chem 267:20392-20399, 1992). The sequence of rodent exon N was not conserved in the human gene. Northern blot analysis of mRNA purified from the human neuroepithelioma cell lines LA-N2 and MC-I-XC revealed that both exons R and M were transcribed in mRNA species of 6.0 and 2.5 kb. Only the 6-kb species was detected with both R- and M-specific probes in the neuroepithelioma cell line CHP126. Reverse transcription-polymerase chain reaction (RT-PCR) analysis suggested that the major mRNA species in MC-I-XC and CHP126 cells contained the proximal part of exon M spliced to exon 1, which contains the alternative ACG initiation codon. RT-PCR also allowed the characterization of a mRNA species containing exon R spliced to exon 1, but no species containing both exon R and the distal part of exon M could be detected. RT-PCR was also used to evidence an alternative exon (tentatively numbered exon 8) in the coding sequence.
authors.affiliation: Laboratoire de Biologie Moléculaire Eucaryote, Centre National de la Recherche Scientifique, Toulouse, France.
authors.forename: M A
authors.initials: MA
authors.lastname: Chireux
authors.forename: A
authors.initials: A
authors.lastname: Le Van Thai
authors.forename: M J
authors.initials: MJ
authors.lastname: Weber
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002478:Cells, Cultured; D002795:Choline O-Acetyltransferase / Q000235:genetics*; D003001:Cloning, Molecular; D005091:Exons / Q000235:genetics*; D005796:Genes; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic
chemical_list: D002795:Choline O-Acetyltransferase