TI  - Characterization of the   <prot>retinoblastoma</prot>   binding proteins  <prot>RBP1</prot>  and  <prot>RBP2</prot> .
PG  - 3149-56
AB  - The <prot>retinoblastoma</prot> gene product, <prot>pRB</prot>, regulates cell proliferation by
      binding to and inhibiting the activity of key growth promoting proteins.
      Several cellular proteins have been shown to bind directly to  <prot>pRB</prot>  and the
      genes encoding a number of them have been isolated. The protein product of
      one of these genes is the transcription factor  <prot>E2F</prot> . We have now isolated
      cDNA clones that contain the full-length coding sequence of two other
      proteins,  <prot>RBP1</prot>  and  <prot>RBP2</prot> , cloned originally by their interaction with   <prot>pRB</prot>  .
      The products of the <prot>RBP1</prot> and <prot>RBP2</prot> genes are ubiquitously expressed, large
      (200 kDa for <prot>RBP1</prot> and 195 kDa for <prot>RBP2</prot>) nuclear phosphoproteins with
      structural motifs that suggest a role in transcriptional regulation. In
      addition we have been able to identify complexes of  <prot>pRB</prot>  and  <prot>RBP1</prot>  in vivo
      that are dissociated in the presence of purified human papillomavirus <prot>E7</prot>
      protein.
AD  - Massachusetts General Hospital Cancer Center, Charlestown 02129.
