MOLECULAR-CLONING OF A HUMAN PROTEIN THAT BINDS TO THE RETINOBLASTOMAPROTEIN AND CHROMOSOMAL MAPPING

We have isolated distinct clones for cellular proteins that bind to th e retinoblastoma protein by direct screening of cDNA expression librar ies using purified PRE as a probe. The total nucleotide sequence of on e of these clones, RBQ-3, was determined and found to encode a protein of 66 kDa localized in the nucleus, The RBQ-3 preferentially binds to underphosphorylated pRB. The region used for binding to this protein was mapped to the E1A-binding pocket B of pRB, which has sequence simi larity to the general transcription factor TFIIB. We have mapped the g ene to 1q32 using polymerase chain reaction analysis on a human-hamste r hybrid cell panel and chromosomal fluorescence in situ hybridization . (C) 1995 Academic Press, Inc.