The Molecular Basis of the Response to Radiation

Abstract : This is the first year of this three year IDEA Award. The most challenging aspect of this project is the isolation of novel cDNAs encoding human homologs of yeast DNA damage response genes. To date complementation of the yeast mutant rad9 have not yielded human cDNAs with significant homology. Thus, over the last year we have made a major effort to isolate cDNAs by degenerate PCR strategies which is still underway. In addition, the use of specific two hybrid screens using known human DNA damage response/cell cycle genes has resulted in the isolation of human homologs ofRADJ8 and RAD2l. The subsequent objectives are focused on determination of whether cDNAs isolated in genetic screens are altered in expression or structure in breast cancers. The reagents including RNA, DNA and protein from human breast cancer cell lines grown under identical culture conditions were produced during the first year of the companion CDA award. This set of reagents has been used and demonstrated increased expression of the RAD2l RNA in some breast cancer cell lines. This prompted the development of a Rad2l antibody which has been completed and will be used for analysis of protein expression in these lines and murine models of mammary tumorigenesis in subsequent years of the grant.