Abstract
Stem cells require different types of supporting cells, or niches, to control stem cell maintenance and differentiation. However, little is known about how those niches are formed. We report that in the development of the Drosophila melanogaster ovary, the Hedgehog (Hh) gradient sets differential cell affinity for somatic gonadal precursors to specify stromal intermingled cells, which contributes to both germline stem cell maintenance and differentiation niches in the adult. We also report that Traffic Jam (an orthologue of a large Maf transcription factor in mammals) is a novel transcriptional target of Hh signaling to control cell-cell adhesion by negative regulation of E-cadherin expression. Our results demonstrate the role of Hh signaling in niche establishment by segregating somatic cell lineages for differentiation.
Highlights
Stem cells reside in microenvironments, called niches, formed to recruit stem cells during development and regulate stem cell identify and behavior in adults (Jones and Wagers, 2008)
Knockdown cells are excluded from the intermingled cells (ICs) region. These results suggest that Hh signaling controls the segregation of ICs and basal cells via control of cell-cell adhesion, an effect that is mediated by Traffic Jam (Tj)–E-cadherin regulation
We used UAS-gfp driven by hh-GAL4 (Sarikaya and Extavour, 2015) to mark hh-expressing cells. hh-GAL4 was expressed in somatic gonadal precursors (SGPs) by the early L2 stage (Fig. 1, A, B, F, G, K, and L), and its expression was restricted to disc-shaped cells, Figure 2
Summary
Stem cells reside in microenvironments, called niches, formed to recruit stem cells during development and regulate stem cell identify and behavior in adults (Jones and Wagers, 2008). The anterior-most structure of the ovariole, the germarium (Fig. 2 C), houses two to three GSCs; each of their fusomes faces cap cells (a major GSC maintenance niche component), which are adjacent to basal TFs (Kirilly and Xie, 2007). The entire structure buds off from the germarium to form a new egg chamber, which develops into a mature egg. The loss of cap cells results in GSC loss (Song et al, 2007; Hsu and Drummond-Barbosa, 2009), and dysfunction of escort cells causes accumulation of undifferentiated GSCs (Jin et al, 2013; Wang et al, 2015), signifying the importance of these niches. How niche cap and escort cells are specified is unclear
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
