The transcription elongation factors Spt4 and Spt5 control neural progenitor proliferation and are implicated in neuronal remodeling during mushroom body development.

Spt4 and Spt5 form the DRB sensitivity inducing factor (DSIF) complex that regulates transcription elongation at multiple steps including promotor-proximal pausing, processivity and termination. Although this implicated a general role in transcription, several studies pointed to smaller sets of target genes and indicated a more specific requirement in certain cellular contexts. To unravel common or distinct functions of Spt4 and Spt5 , we generated knock-out alleles for both genes in .