Characterization of the human apobec-1 gene: expression in gastrointestinal tissues determined by alternative splicing with production of a novel truncated peptide

Autor: K Hirano, J Min, T Funahashi, D A Baunoch, N O Davidson
Jazyk: angličtina
Rok vydání: 1997
Předmět:
Zdroj: Journal of Lipid Research, Vol 38, Iss 5, Pp 847-859 (1997)
Druh dokumentu: article
ISSN: 0022-2275
DOI: 10.1016/S0022-2275(20)37210-2
Popis: In humans, both the expression of apobec-1 and the C to U deamination of apoB mRNA are confined to the small intestine. In order to understand the tissue-restricted pattern of apobec-1 expression, we have isolated the chromosomal gene spanning the human apobec-1 locus. The human apobec-1 gene spans 18 kb and contains five exons, all of which are translated. Transcription initiation, determined by RNase protection and primer extension analyses, is localized to a single start site 34 nt upstream of the open-reading frame in exon 1. A common, but functionally silent, gene polymorphism was detected than changes Ilc80 to MCl. RNase protection and reverse-transcription PCR analysis demonstrated the presence of an exon 2-skipped form of apobec-1 mRNA that arises through use of an alternative splice acceptor. This alternative splicing causes a frame-shift that produces a novel, 36 amino acid peptide. The exon 2-skipped form accounts for approximately 50% of apobec-1 mRNA in the adult small intestine and up to 90% of apobec-1 mRNA in the developing gut. An antipeptide antibody identified the truncated protein in villus cells of the adult small intestine. These data suggest that exon 2-skipping may represent an important control mechanism regulating apobec-1 gene expression in humans.
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