IDENTIFICATION OF A NOVEL HUMAN RAD51 HOMOLOG, RAD51B

The highly conserved Saccharomyces cerevisiae RAD51 protein functions in both mitotic and meiotic homologous recombination and in double-str and break repair. Screening of the public cDNA sequence database for R AD51-like genes led to the identification of a partial sequence from a breast tissue library present in the I.M.A.G.E. (Integrated Molecular Analysis of Genes and their Expression) collection. An extended 1764- bp cDNA clone encoding an open reading frame of 350 amino acids was is olated. This clone showed significant amino acid identity with other h uman RAD51 homologs. The new homolog, named RAD51B, was mapped to huma n chromosome 14q23-q24.2 using a panel of human-hamster somatic cell h ybrids and fluorescence in situ hybridization. Northern blot analysis demonstrated that RAD51B mRNA is widely expressed and most abundant in tissues active in recombination. Functions associated with known RAD5 1 homologs suggest a role for RAD51B in meiotic recombination and/or r ecombinational repair. (C) 1997 Academic Press.