JAK-STAT signal inhibition regulates competition in the Drosophila testis stem cell niche - PubMed (original) (raw)

Figure 1. socs36E is required to maintain germline stem cells

(A to E) Confocal section through the testis apex immunostained with [(A) and (B)] antibody to Vasa (germline, red), antibody to Fasciclin III (hub, green), antibody to Hts (1B1 fusome, green), and 4′,6′-diamidino-2-phenylindole (DAPI) (DNA, blue) or with [(D) and (E)] antibody to Vasa (red), antibody to ZFH-1 (CPCs and their immediate daughters, green), and DAPI (blue). The hub is outlined. (A) In wild-type testes, a rosette of GSCs (one indicated, arrow) surrounds the hub; Vasa-negative CPCs (one indicated, arrowhead) make minimal contact with the hub. (B) socs36EPZ1647 testes have fewer GSCs (arrow); instead, somatic cells (arrowhead) surround the hub. (C) Bar graph showing number of GSCs per testis. Homozygous mutant socs36EPZ1647 testes contain significantly fewer GSCs than do wild-type (red, 3.8 ± 0.2, n = 12 testes, versus yellow, 9.9 ± 0.4, n = 14 testes, P < 0.0001) or socs36E heterozygotes (green, 9.5 ± 0.4, n = 14 testes). Testes from socs36EPZ1647 in trans to a deletion of socs36E (Df(2L)M36F-S5) phenocopy socs36EPZ1647 (blue, 4.0 ± 0.2, n = 12 testes). Leaky expression from a socs36E cDNA transgene rescues the phenotype (gray, 8.9 ± 0.7 GSCs, n = 15 testes). Precise excision of the P-element restores GSC number to wild-type (white, 9.6 ± 0.6, n = 11 testes). (D) In wild-type testes, GSCs surround the hub; nuclei of ZFH-1–positive CPCs (arrowhead) are displaced from the hub. (E) In socs36EPZ1647, CPCs (arrowhead) occupy positions at the hub that usually contain GSCs. (F and G) Ultrastructural analysis of the testis niche. Hub cells (red), GSCs (yellow), and a gonialblast (blue), identified by differences in morphology and staining density (29), are indicated. (F) In wild-type testes, GSCs make broad contact with the hub; CPCs extend thin projections (arrowheads) between GSCs. (G) In socs36EPZ1647, CPCs broadly contact the hub, whereas GSCs make small areas of contact with the hub (rectangle). Scale bars, 10 μm.