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 UBF 2, except for a 37 amino acid insertion found in UBF1. This insertion is completely conserved among mammalian UBF1 which indicates a putativ e role of this region on the function of this transcript.