Project description:The determination of glial fate in the developing embryonic nervous system of Drosophila is dependent on the master regulatory gene glial cells missing (gcm). gcm encodes a transcription factor and serves as a binary switch by inducing the glial fate and repressing the neuronal pathway. The ectopic expression of gcm throughout the CNS leads to excessive glia on the cost of presumptive neurons, whereas gcm loss-of-function embryos lack nearly all lateral glial cells. To date only little is known about the genetic program underlying glial differentiation. In order to identify glial specific genes downstream of gcm we performed a whole-genome microarray approach, where we compared the gcm gain-of-function situation (GOF) and, for the first time, the gcm loss-of-function (LOF) against wildtype in a time course experiment throughout embryogenesis. Intense filtering of differentially regulated genes on behalf of statistics as well as developmental means such as profile of differential regulation enabled us to identify more than 40 novel glial genes. The confirmation of these genes by in situ hybridization revealed temporal expression profiles in all or subsets of glial cells. We give a detailed description of the expression patterns of the candidate genes and adress their regulation in the glial pathway in different glial mutant backgrounds. Additionally we started to analyze mutant phenotypes of candidate genes to clarify their functional relevance for glial differentiation. Keywords: Drosophila,gliogenesis,time course,loss-of-function,gain-of-function
