Professor Tower's research primarily focuses on the following two areas: the molecular genetics of aging in Drosophila and Drosophila chorion gene amplification. He is taking two approaches to his research on aging, the first of which identifies genes that directly regulate life span. His current emphasis with these techniques is to test candidate genes involved in regulating oxidative stress responses, DNA repair, and nuclear-mitochondrial signaling. He is particularly interested in how the post-mitotic muscle and nerve cells of the adult maintain function during aging, and how stem cells populations are maintained in the ovary. The second general approach he uses is studying the regulation of heat shock gene expression as a function of age, in particular the hsp70 and hsp22 genes. He is pursuing a detailed analysis of the transcriptional and posttranscriptional regulation of the Drosophila hsp70 and hsp22 genes as a model for this species-general aspect of aging. In his investigation of chorion gene amplification, Professor Tower has cloned and characterized two amplification trans-regulators, k43 and chiffon, and found that they are related to origin regulatory proteins in yeasts, ORC2 and Dbf4 respectively. Prior analysis of cis-sequence elements and their relationship to origins was hampered by severe chromosomal position effects. He found that flanking the ends of transgenic constructs with transcriptional insulator elements, called "Suppressor of Hairy-wing protein binding sites" (SHWBSs) protected the constructs from position effects. The data implicated chromatin structure in origin regulation, and provided a powerfully improved assay. Using such buffered constructs he has been able to analyze cis-sequence requirements and functions in detail. Professor Tower found that functionally distinct, sequence-specific replicator and origin elements are required for amplification
