The Osa-Containing SWI/SNF Chromatin-Remodeling Complex Is Required in the Germline Differentiation Niche for Germline Stem Cell Progeny Differentiation

• Main Authors: Xiaolong Hu, Mengjie Li, Xue Hao, Yi Lu, Lei Zhang, Geng Wu
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: Genes
• Subjects: germline stem cell; Drosophila ovary; escort cell; differentiation niche; decapentaplegic; engrailed
• Online Access: https://www.mdpi.com/2073-4425/12/3/363

The <i>Drosophila</i> ovary is recognized as a powerful model to study stem cell self-renewal and differentiation. Decapentaplegic (Dpp) is secreted from the germline stem cell (GSC) niche to activate Bone Morphogenic Protein (BMP) signaling in GSCs for their self-renewal and is restricted in the differentiation niche for daughter cell differentiation. Here, we report that Switch/sucrose non-fermentable (SWI/SNF) component Osa depletion in escort cells (ECs) results in a blockage of GSC progeny differentiation. Further molecular and genetic analyses suggest that the defective germline differentiation is partially attributed to the elevated <i>dpp</i> transcription in ECs. Moreover, ectopic Engrailed (En) expression in <i>osa</i>-depleted ECs partially contributes to upregulated <i>dpp</i> transcription. Furthermore, we show that Osa regulates germline differentiation in a Brahma (Brm)-associated protein (BAP)-complex-dependent manner. Additionally, the loss of EC long cellular processes upon osa depletion may also partly contribute to the germline differentiation defect. Taken together, these data suggest that the epigenetic factor Osa plays an important role in controlling EC characteristics and germline lineage differentiation.