Tbx1 ortholog is required to establish testis stem cell niche identity in .

Stem cells require signals from a cellular microenvironment known as the niche that regulates identity, location, and division of stem cells. Niche cell identity must be properly specified during development to form a tissue capable of functioning in the adult Here, we show that the Tbx1 ortholog is expressed in testis niche cells in response to Slit and FGF signals. is expressed during niche development and is required to specify niche cell identity. mutants specified fewer niche cells, and those cells showed disruption of niche-specific markers, including loss of the niche adhesion protein Fas3 and reduced expression. We found that expression in somatic gonadal precursors is capable of inducing formation of additional niche cells. Disrupted niche identity in mutants resulted in niche assembly and functionality defects. We find the conserved transcription factor is expressed in response to and show that functions downstream to mediate niche identity and assembly. This work identifies a novel role for in niche establishment.