Hepatoma-derived growth factor belongs to a gene family in mice showing significant homology in the amino terminus.
Hepatoma-derived growth factor (HDGF) is an acidic polypeptide with mitogenic activity for fibroblasts performed outside the cells despite the presence of a putative nuclear localization signal (NLS). We have now cloned three related mouse cDNAs: one for a mouse homologue of human HDGF and two for additional HDGF-related proteins provisionally designated HDGF-related proteins 1 and 2 (HRP-1 and -2). Their deduced sequences have revealed that HDGF belongs to a new gene family with a highly conserved 98-amino-acid sequence at the amino terminus (hath region, for homologous to the amino terminus of HDGF). HRP-1 and HRP-2 proteins are 46 and 432 amino acids longer than mouse HDGF, respectively, and have no conserved amino acid sequence other than the hath region. HRP-1 is a highly acidic protein (26% acidic) and also has a putative NLS. HRP-2 protein carries a mixed charge cluster, a sharp switch of positive-to negative-charge residues, which is often found in some nuclear proteins. Northern blotting shows that mouse HDGF and HRP-2 are expressed predominantly in testis and skeletal muscle, to intermediate extents in heart, brain, lung, liver, and kidney, and to a minimal extent in spleen. HRP-1 is expressed specifically in testis. These findings suggest that the HDGF gene family might play a new role in the nucleus especially in testis.
Izumoto
Y
Y
Department of Medicine III, Osaka University Medical School, Suita, Japan.
Kuroda
T
T
Harada
H
H
Kishimoto
T
T
Nakamura
H
H
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000302:isolation & purification; D005786:Gene Expression Regulation; D006133:Growth Substances / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D005810:Multigene Family; D017386:Sequence Homology, Amino Acid
D000596:Amino Acids; D018076:DNA, Complementary; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; C051610:hepatoma-derived growth factor