Smad-Independent BMP Signaling in Somatic Cells Limits the Size of the Germline Stem Cell Pool.
Stem Cell Reports 2018;
11:811-827. [PMID:
30122445 PMCID:
PMC6135924 DOI:
10.1016/j.stemcr.2018.07.008]
[Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/22/2022] Open
Abstract
In developing organisms, proper tuning of the number of stem cells within a niche is critical for the maintenance of adult tissues; however, the involved mechanisms remain largely unclear. Here, we demonstrate that Thickveins (Tkv), a type I bone morphogenetic protein (BMP) receptor, acts in the Drosophila developing ovarian soma through a Smad-independent pathway to shape the distribution of BMP signal within the niche, impacting germline stem cell (GSC) recruitment and maintenance. Somatic Tkv promotes Egfr signaling to silence transcription of Dally, which localizes BMP signals on the cell surface. In parallel, Tkv promotes Hh signaling, which promotes escort cell cellular protrusions and upregulates expression of the Drosophila BMP homolog, Dpp, forming a positive feedback loop that enhances Tkv signaling and strengthens the niche boundary. Our results reveal a role for non-canonical BMP signaling in the soma during GSC establishment and generally illustrate how complex, cell-specific BMP signaling mediates niche-stem cell interactions.
Tkv, a BMP receptor, in the developing ovarian soma controls fertility
Knockdown Tkv in the developing soma causes ectopic germline stem cell (GSC) accumulation
Tkv in the soma controls GSC number by limiting BMPs within the GSC niche
BMP-Tkv signaling in the soma limits GSC number via Egfr and Hh signaling
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