cDNA sequence and structure of a trout HMG-2 gene. Evidence for a trout-specific 3'-untranslated region.
A complete cDNA sequence (1026 bp) and a partial structure of a gene encoding the trout testis chromosomal HMG (high mobility group) 2 protein (HMG-T2) is presented. The deduced protein consists of 214 amino acids and shares over 80% similarity to the trout HMG-1 protein (HMG-T1) as well as to the mammalian or avian HMG-2 proteins. Northern blot analysis revealed two transcripts, a major one of 1.2 kb and a minor one of 1.6 kb. Southern analysis and polymerase chain reaction of trout genomic DNA indicated that the HMG-T2 gene is encoded by several introncontaining genes. The 5'-UTR (untranslated region) of the HMG-T2 is interrupted by an intron and the coding region of the HMG-T2 is divided into four exons by three relatively short introns (173, 91 and 78 bp). The exon/intron boundaries of trout HMG-2 are identical to those of human HMG-2, as reported earlier [Shirakawa and Yoshida, J. Biol. Chem. 267 (1992) 6641-6645], suggesting the evolution of the HMG-1/2 family genes from a common ancestor. Phylogenetic analysis indicated that the common ancestor of trout HMG-1/2 genes very likely diverged from the ancestor of the mammalian (or avian) HMG-1/2 genes before its separation into two distinct mammalian or (avian) HMG-1 and HMG-2 genes. Sequence comparisons of the 3'UTR of trout HMG-2 cDNA with the corresponding regions in the mammalian (or avian) HMG-2 revealed that the trout 3'-UTR was clearly distinct from the 3'-UTR of the mammalian or avian HMG-2 cDNAs which were otherwise remarkably well conserved.(ABSTRACT TRUNCATED AT 250 WORDS)
Stros
M
M
Department of Biochemistry, University of Calgary, Alberta, Canada.
Retief
J D
JD
Dixon
G H
GH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D015152:Blotting, Northern; D015139:Blotting, Southern; D018076:DNA, Complementary / Q000235:genetics; D005091:Exons / Q000235:genetics; D016678:Genome; D006609:High Mobility Group Proteins / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D013737:Testis; D014337:Trout / Q000235:genetics*
D018076:DNA, Complementary; D006609:High Mobility Group Proteins