poly-A RNA profiling of Drosophila intermediate neural porgenitors (INPs) of three different temporal states reveal genes involved in temporal patterning

Neural stem cells (NSCs) generate highly diverse neurons over time by acquiring new features, a phenomenon called as temporal patterning. However the mechanisms underlying temporal patterning still remains poorly understood. Here, we describe a method that allows to isolate different temporal stages of Drosophila transit amplifying cells called intermediate neural porgenitors (INPs). We identified odd-paired (opa) as the regulator of the transition from first to second temporal stages, which are defined by D and Grh expression. We demonstrated that opa is required for correct neural output and brain morphology. We showed that opa achieves this transition via repressing D. Together with upstream SWI/SNF complex, D and opa forms an incoheren feed forward loop, which results in successive expression of temporal identities. Overall design: Comparison of transcriptomes of wild-type INPs of different temporal stages (D+, Grh+ or Ey+) isolated by FACS from Drosophila melanogaster larval brains