PROJECT ABSTRACT My laboratory's long-term goal is to improve our understanding of growth, metabolism, and cell cycle regulation during Drosophila development. This proposal focuses on the molecular identification and functional characterization of fried. The three fried mutants were identified in the same EMS clonal screen that identified mutants in gatA, the gene that we characterized in meeting the specific aims of NIH R15 grant GM074735-01. As with gatA, mutant clones of fried in the germ cells of the ovary result in chromosome morphology defects in the nurse cells and oocyte followed by egg chamber arrest and degradation (Morris, Navarro et al. 2003). In addition, both mutants show growth defects and developmental arrest, though the fried larvae are more variable in size than gatA, and fried mutants arrest development post-pupariation while gatA mutants arrest as larvae (Morris, Bergman et al. 2008) Study of fried is highly significant because understanding fried will likely shed light on control of growth and cell cycle regulation. The initiatives proposed in this grant are additionally significant because they will greatly enhance the research program at Fordham College at Lincoln Center and will enable the training of 6-10 undergraduates in genetics and cell biology research. No other lab is studying fried, so the work proposed here is very unlikely to be performed elsewhere. Specific Aim 1: To characterize the growth and arrest phenotypes and to describe cell cycle defects in the fried EMS alleles. Specific Aim 2: To identify the gene defined by the mutant fried alleles by candidate gene sequencing and transgenic rescue, to molecularly and genetically characterize these alleles, and to determine the fried expression pattern by RTPCR and in situ hybridization. Specific Aim 3: To analyze the function of fried by using Western Blotting and Immunohistochemistry to expression and activation of growth regulators in fried mutants and by using genetic assays to determine which pathways interact with fried mutations. PUBLIC HEALTH RELEVANCE: PROJECT NARRATIVE Drosophila lacking fried gene function grow poorly and arrest development. Appropriate regulation of growth is one of the most fundamental aspects of development, and many regulators of growth in Drosophila also have essential functions in humans. We propose to identify which gene is disrupted in fried mutants and to determine the function of fried in wild type Drosophila.