Fig. 6. A model for Stwl function in repressing the transcription of germ cell differentiation-promoting factors. In wild-type GSCs (top), transcriptional quiescence of bam, via the Dpp signaling cascade, allows full Nos-Pum translational repression of differentiation-promoting mRNAs. Stwl represses the transcription of these mRNAs, probably through interaction with and/or modification of histones. In stwl^- GSCs (bottom), the absence of Stwl function upregulates transcription, thereby increasing the pool of differentiation-promoting mRNAs and promoting cystoblast differentiation despite full Nos-Pum activity.