title: The Gas7 gene encodes two protein isoforms differentially expressed within the brain.
abstract: Gas7, a growth arrest-specific gene first isolated from serum-starved NIH3T3 cells, is expressed abundantly in the brain and is essential for the outgrowth of neurites from cultured cerebellar neurons. Here, we report the existence of a Gas7-related cDNA, designated Gas7-cb, isolated from the mouse cerebellum, and we report the finding that Gas7-cb transcripts and protein are expressed at different locations than those of Gas7. Gas7-cb cDNA differs from the Gas7 cDNA only in the 5' region. Its encoded protein shares the same 320 amino acids in its C-terminus with those of Gas7. Analyses of the RNA and protein expression of Gas7-cb and Gas7 by RNase protection assay and Western blot indicated that while Gas7 expression is predominant in the cerebrum and in growth-arrested NIH3T3 fibroblasts, Gas7-cb expression is predominant in the cerebellum. Characterization of Gas7 and Gas7-cb RNAs and of the genomic structure of murine Gas7 cloned in a bacterial artificial chromosome indicated that the Gas7 gene spans more than 60 kb and consists of at least 15 exons. The 5'-terminus of Gas7-cb is located at exon 6a, which is absent in Gas7 transcripts but is retained in its entirety in Gas7-cb transcripts, resulting in the presence of a unique 20-amino-acid sequence at the N-terminus of the Gas7-cb protein. Our results show that the Gas7 gene encodes two Gas7 isoforms, Gas7 and Gas7-cb, whose expression is differentially regulated within mouse brain.
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Nankang, 115, Taiwan.
authors.forename: E M
authors.initials: EM
authors.lastname: Lazakovitch
authors.forename: B R
authors.initials: BR
authors.lastname: She
authors.forename: C L
authors.initials: CL
authors.lastname: Lien
authors.forename: W M
authors.initials: WM
authors.lastname: Woo
authors.forename: Y T
authors.initials: YT
authors.lastname: Ju
authors.forename: S
authors.initials: S
authors.lastname: Lin-Chao
mesh_terms: D016475:3T3 Cells; D020121:5' Untranslated Regions / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D002874:Chromosome Mapping; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D005091:Exons / Q000235:genetics; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D020121:5' Untranslated Regions; D018076:DNA, Complementary; C485435:Gas7 protein, mouse; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D012260:Ribonucleases