Identification and characterization of RAD9B, a paralog of the RAD9 checkpoint gene

Genomics. 2003 Dec;82(6):644-51. doi: 10.1016/s0888-7543(03)00200-3.

Abstract

RAD9 is an integral element of the PCNA-like HUS1-RAD1-RAD9 (9-1-1) complex that participates in genotoxin-induced CHK1 activation. We have identified a novel RAD9 paralog, dubbed RAD9B, in humans and mice. RAD9 and RAD9B share extensive amino acid homology throughout their entire sequences (36% identity, 48% similarity). Northern blotting revealed that RAD9B transcripts are highly expressed in human testes, with lower levels found in skeletal muscle. In contrast, RT-PCR analysis and immunoprecipitation demonstrated that RAD9B is also expressed in tumor cells. Like RAD9, RAD9B associates with HUS1, RAD1, and RAD17, suggesting that it is a RAD9 paralog that engages in similar biochemical reactions. In addition, we have also shown that RAD9 and RAD9B interact with the HUS1 paralog, HUS1B. Taken together, these results suggest that these proteins can combinatorially assemble into distinct 9-1-1 clamps that may have distinct biological functions.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Baculoviridae
  • Base Sequence
  • Blotting, Northern
  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • DNA Primers
  • Electroporation
  • Gene Expression*
  • Genetic Vectors
  • Humans
  • Male
  • Mice
  • Molecular Sequence Data
  • Muscle, Skeletal / metabolism
  • Precipitin Tests
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Homology
  • Testis / metabolism

Substances

  • Cell Cycle Proteins
  • DNA Primers
  • HUS1 protein, human
  • HUS1B protein, human
  • rad9 protein