View Program - 63rd Annual Drosophila Research Conference

Stem cells are important for repairing and regenerating our tissues, and often reside in a niche that controls their behavior. The testis niche has been a paradigm for niche-stem cell interactions. Recently, our lab has focused on the construction of this niche. Examining initial assembly of the niche in embryonic gonads has revealed both how extra-gonadal signals drive niche assembly (Anllo and DiNardo, 2021), and begun illuminating the cell mechanics involved in first forming a compact, functional niche (B. Warder poster). Here we use the adult testis niche to address the cell biological features that maintain niche structure and function during its steady-state operation. The niche resides at the testis tip and is comprised of a group of quiescent cells that send renewal signals to the neighboring stem cells. These quiescent cells are organized spherically, and are radially surrounded by two stem cell populations, the germline stem cells and the cyst stem cells. Our preliminary evidence suggests that acto-myosin contractility (AMC) is important for the maintenance of the spherical nature of the stem cell niche. The recently released single nuclear, RNA-SEQ Fly Cell Atlas (FCA) for the testis is a resource to suggest genes that might be candidates involved in niche structure. Center-divider (cdi) is suggested as enriched in the niche based on the FCA data and encodes a serine/threonine kinase known to induce actin remodeling through phosphorylation of cofilins. Our preliminary evidence shows that knockdown of cdi indeed affects maintenance of testis niche structure. We therefore hypothesize that the AMC and actin remodeling are both important for preserving niche structure and potentially critical for the maintenance of stem cells.

Identifying factors that maintain the adult testis niche