TI  - The  <prot>retinoblastoma</prot> protein  binds to  <prot>RIZ</prot> , a zinc-finger protein that shares
      an epitope with the adenovirus <prot>E1A</prot> protein.
PG  - 4467-71
AB  - The <prot>retinoblastoma protein</prot> (<prot>Rb</prot>) is a target of viral oncoproteins. To
      explore the hypothesis that viral proteins may be structural mimics of
      cellular proteins, we have searched cDNA libraries for <prot>Rb</prot>-binding
      proteins. We report here the cloning of a cDNA for the protein <prot>RIZ</prot> from
      rat and human cells. <prot>RIZ</prot> is a 250-kDa nuclear protein containing eight
      zinc-finger motifs. It contains an <prot>Rb</prot>-binding motif that shares an
      antigenic epitope with the C terminus of <prot>E1A</prot>. A domain is conserved
      between <prot>RIZ</prot> and the <prot>PRDI-BF1</prot>/<prot>Blimp-1</prot> differentiation factor. Other motifs
      of <prot>RIZ</prot> include putative GTPase and SH3 (src homology domain 3) domains.
      <prot>RIZ</prot> is preferentially expressed in both adult and embryonic rat
      neuroendocrine tissues. It is also expressed in human retinoblastoma cells
      and at low levels in all other human cell lines examined. While the
      function of <prot>RIZ</prot> is not yet clear, its structure and pattern of expression
      suggest a role for <prot>RIZ</prot> in transcriptional regulation during neuronal
      differentiation and pathogenesis of retinoblastoma.
AD  - Cancer Research Center, La Jolla Cancer Research Foundation, CA 92037,
