Glia development in the embryonic CNS of Drosophila

The major axon tracts in the embryonic CNS of Drosophila are organized in a simple, ladder like pattern. Each neuromere contains two commissures which connect the contra-lateral hemi-neuromeres and two longitudinal connectives which connect the different neuromeres along the anterior-posterior axis. The formation of these axon tracts occurs in close association with different glial cells. Loss of specific glial cells within the CNS leads to predictable defects in the organization of the CNS axon pattern. To unravel the genes underlying CNS glia development, we have conducted a saturating F2 EMS mutagenesis, screening for mutations, which disrupt axon pattern in the embryonic nervous system. We found a large number of mutations that lead to phenotypes indicative for glia defects. The analysis of the genes identified, show that glial cell differentiation requires the function of two independent regulatory pathways.