Polycomb Group Ring Finger Protein 4 (PCGF4)

Infection of E-mu/myc transgenic mice with Moloney murine leukemia virus (MuLV) is an efficient way to identify oncogenes that synergize with the transgene. In about half of independently induced pre-B-cell lymphomas, the provirus integrates in or near the Bmi1 gene, resulting in enhanced transcription of that gene. The murine Bmi1 protein is found in the nucleus and harbors structural motifs found in nuclear proteins, including a novel putative zinc finger shared by a diverse set of proteins involved in gene regulation, DNA recombination, and DNA repair. The product of the Bmi1 gene showed 70% identity with the Mel18 protein gene, which was isolated from a mouse melanoma cell line. The Bmi1 gene is highly conserved in evolution as indicated by zoo blot hybridization with Bmi1 probes corresponding to the protein-encoding domain.