Cloning and sequencing of the genes encoding the hamster ribosomal transcription factors UBF1 and UBF2.

The RNA polymerase I transcription factor, UBF, belongs to a family of high-mobility-group DNA-binding proteins. Here, a human autoantibody reactive with the nucleolus organizer regions (NOR) was used to select cDNA clones encoding the hamster transcription factors, UBF1 and UBF2. Comparison at the nucleotide level showed a high degree of homology with other mammalian upstream binding factors (UBF) already identified. The deduced amino acid sequences are identical for both UBF1 and UBF2, except for a 37 amino acid insertion found in UBF1. This insertion is completely conserved among mammalian UBF1 which indicates a putative role of this region on the function of this transcript.