title: Identification and characterization of RAD9B, a paralog of the RAD9 checkpoint gene.
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.
authors: Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
authors: Vanessa M
authors: VM
authors: Dufault
authors: Andrea J
authors: AJ
authors: Oestreich
authors: Benjamin T
authors: BT
authors: Vroman
authors: Larry M
authors: LM
authors: Karnitz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae; D001483:Base Sequence; D015152:Blotting, Northern; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D017931:DNA Primers; D018274:Electroporation; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D011233:Precipitin Tests; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D013737:Testis / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D017931:DNA Primers; C549605:HUS1 protein, human; C462949:HUS1B protein, human; C069930:rad9 protein