Identification of a YAC from 16q24 carrying a senescence gene for breast cancer cells

We have identified a 360 kb YAC that carries a cell senescence gene, SEN16. In our earlier studies, we localized SEN16 within a genetic interval of 3- 7 cM at 16q24.3. Six overlapping YACs spanning the chromosomal region of se nescence activity, were assembled in a contig. Candidate YACs, identified b y the markers located in the vicinity of SEN16, were retrofitted to introdu ce a neo selectable marker. Retrofitted YACs were first transferred into mo use A9 cells to generate A9/YAC hybrids. YAC DNA present in A9/YAC hybrids was further transferred by microcell fusion into immortal cell lines derive d from human and rat mammary tumors. YAC d792t2 restored senescence in both human and rat mammary tumor cell lines, while an unrelated YAC from chromo some 6q had no senescence activity.