Issues

Cover: Germline-specific downregulation of Rtf1, the subunit of the chromatin remodeling Paf1 complex required for histone H2B modification, leads to severe defects in Drosophila germline differentiation, resulting in the arrested egg production and dramatically reduced ovary size (nanosGal4>UAS Rtf1 RNAi; nuclei are marked in green, magenta represents LaminC+Adducin). In response to stress, steroid-dependent miRNA let-7 regulates cellular identity of somatic escort cells, forming the germline differentiation niche that communicates with the germline via the cell adhesion-mediated Wingless (Wg) signaling. The Wingless pathway acts in the germline and establishes the specific chromatin status, promoting germline stem cell progeny differentiation. In particular, histone H2B monoubiquitination is delayed upon ecdysone/Wg deficit, postponing expression of differentiation genes required for the germline stem cell progeny to enter the differentiation program. Photo credit: Halyna R Shcherbata. See the article by König and Shcherbata. (doi: 10.1242/bio.201410553).