We are using a combination of functional genomics approaches and microarray analysis techniques to identify and clone human senescence genes. One area of focus is identification of a gene in the region of human chromosome 1q42. Past studies of microcell-mediated chromosome transfer experiments revealed senescence gene activity on human chromosome 1. Subsequent analyses of revertants and radiation-induced selectable tagged fragments of chromosome 1 further narrowed the region of activity to a 5-cM region on 1q42 that is too large to clone using traditional positional cloning methodologies. In one approach to identifying the gene functionally, transfer of commercially available yeast artificial chromosomes from the 1q42 region by spheroplast fusion led to identification of a 1.2-Mb artificial chromosome that contains possible senescence activity, as indicated by decreased colony formation of an immortal cell following spheroplast fusion. Analysis of Gene Map 98 revealed 450 defined candidate genes or expressed sequence tags in the 1q42 region. We developed a complementary DNA microarray chip that contains all these candidate genes and expressed sequence tags. We are conducting microarray analysis using a cDNA microarray chip that contains a total of 12,000 genes and expressed sequence tags, including those from the 1q42 region. We are conducting hybridizations with RNA derived from young, immortal, G1-arrested and senescent fibroblast and epithelial cells to identify critical targets of the senescence and immortalization processes. Our goal is to couple the microarray analysis with our physical and functional mapping approaches to identify the candidate gene on 1q42 that is responsible for inducing the senescence phenotype.