Cloning of the rat proto-oncogene bmi-1

The bmi-1 gene was identified as a common proviral integration site in Moloney murine leukemia virus. In the present studies, we cloned and sequenced the rat bmi-1 gene by reverse transcriptase–polymerase chain reaction (RT-PCR) using degenerate PCR primers of homologous sequences between mouse and human. We found 93% identity to the mouse bmi-1 cDNA and 90% identity to the human bmi-1. The open reading frame encodes a protein of 324 amino acids. In the deduced amino acid sequence we observed 95% and 94% homology to the mouse and human, respectively. The structural motifs, a novel zinc finger motif and a putative helix-turn-helix motif, were conserved in the predicted rat BMI-1 protein. We also confirmed ubiquitous expression of bmi-1 in normal tissues except brain. These results suggest functional conservation of the bmi-1 gene in the rat.