| Cell fate decisions are made throughout development to establish specialized organs and tissues through the actions and directions of specialized gene regulatory networks. Interestingly, many of the genes within these networks are used repeatedly and throughout development to confer the fates of multiple tissues. Additionally, these genes and their cooperative signaling pathways have been highly conserved throughout evolution, thus retaining striking similarities between flies, mice and even humans. My primary research interest is in understanding what factors are required for tissue specification to occur. How is it that, with remarkable consistency, we develop with two hands at the ends of our arms, one nose in the center of our face and two eyes placed symmetrically above our nose? I have used the compound eye of the fruit fly, Drosophila melanogaster, as a system for studying the extensive genetic and molecular interactions required for appropriate specification of retinal tissues. My approaches include (1) investigating the complex regulatory relationship that exists between three core members of the retinal determination network, sine oculis (so), eyes absent (eya) and dachshund (dac); (2) a genetic screen to identify genes that regulate the expression of the dual function transcriptional coactivator and tyrosine phosphatase, eya; (3) creating a detailed map of non-retinal cell populations within the fly that can be converted to an eye fate through the forced expression of one or more RD genes. In accomplishing each of these objectives I have made contributions to the field by identifying novel regulatory relationships between existing members of the retinal determination network and identified new genes that regulate the expression of eya both in the developing retina and the embryonic head (prior to onset of retinogenesis). Further, I have identified weak spots for spontaneous transdetermination as developmentally acquiescent cells that can support retinal development in typically non-retinal tissues. |
