PCCX1, a novel DNA-binding protein with PHD finger and CXXC domain, is regulated by proteolysis.
We identified a novel gene PCCX1 that encoded a nuclear protein carrying a PHD finger, a CXXC domain, and an acidic region. The CXXC domain was found to be sufficient for binding to DNA. The acidic region exhibited a high transactivation ability, but the full-length protein was inactive due to regions which inhibited the acidic region, including the C-terminal region. We examined the expression of PCCX1 during cellular aging and immortalization of SV40-transformed human fibroblasts. PCCX1 mRNA was expressed constitutively through stages of cellular aging and immortalization, but at the protein level, a shorter form lacking the C-terminal region appeared as the cells approached crisis. These results suggested that PCCX1 was activated by proteolytic cleavage, which removed the C-terminal inhibitory region.
Fujino
T
T
Department of Microbiology, Keio University School of Medicine, Shinjuku-ku, Tokyo, 160-8582, Japan.
Hasegawa
M
M
Shibata
S
S
Kishimoto
T
T
Imai
S
S
Takano
T
T
D000595:Amino Acid Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015534:Trans-Activators; D014158:Transcription, Genetic; D014162:Transfection; D020798:Two-Hybrid System Techniques; D016335:Zinc Fingers
C409062:CXXC1 protein, human; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D015534:Trans-Activators; D008156:Luciferases; D005982:Glutathione Transferase