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. Author manuscript; available in PMC: 2011 Jun 4.
Published in final edited form as: Cell Stem Cell. 2010 Jun 4;6(6):557–567. doi: 10.1016/j.stem.2010.04.018

Figure 1. Nurf301 is a unique member of the NURF chromatin remodeling complex and is required for GSC maintenance in the Drosophila testis stem cell niche.

Figure 1

(A) The Drosophila testis apex. Approximately 10 GSCs make broad contact with the hub. GSCs divide asymmetrically to produce gonialblast (GB) daughters that are displaced away from the hub. GBs undergo four rounds of mitosis giving rise to 16-interconnected spermatogonia, which further differentiate into spermatocytes. Approximately two CPCs flank each GSC and contact the hub through thin cytoplasmic extensions. CPCs divide asymmetrically, giving rise to non-mitotic somatic cyst cells that encyst differentiating germ cells. (B) NURF is one of three ISWI-containing ATP-dependent chromatin remodeling complexes in Drosophila. The Nurf301 subunit is unique to the NURF complex and is essential for its function. ACF and CHRAC are distinct from NURF and share a common subunit: ACF1. (C–D) Confocal section of a wild-type testis apex immunostained with germline specific marker anti-Vasa (red), the DNA counterstain DAPI (blue), and (C) anti-ISWI (green, inset) or (D) anti-Nurf301 (green, inset). (C) ISWI is expressed in GSCs (Vasa-positive and contacting the hub, one indicated, arrowhead), CPCs (Vasa-negative and within two cell diameters of the hub, one indicated, arrow) and the hub (*). (D) Nurf301 is expressed in all cell types in the testis apex including GSCs (arrowhead), CPCs (arrow), and the hub (*). (E–F) Testes immunostained with anti-Vasa (red), the hub marker anti-Armadillo (green), the fusome marker anti-1B1 (green) and DAPI (blue). (E) A wild-type testis with a rosette of GSCs surrounding the hub (*). GSCs contain spherical fusomes (green, arrowhead) whereas differentiating spermatogonia contain elongated and branched fusomes (open arrowhead). (F) Projection of three confocal sections of a testis with reduced Nurf301 function (nurf3014/nurf30112) showing differentiating spermatogonia (black outline) containing a branched fusome (open arrowhead) and contacting the hub (white outline). Bars, 10 microns.