(A, B) ken1 heterozygous testes immunostained with anti-Vasa (germline, red), anti- -galactosidase ( -GAL)(Ken, green), and DAPI (DNA, blue). (A) Ken is expressed in the hub (outlined), the CySCs (one indicated, arrowhead), the GSCs (one indicated, arrow), and their differentiating cyst cell (one indicated, open arrowhead) and germline daughters. Scale bar, 10 m. (B) Ken is expressed in the testis apex (outlined), but not in highly differentiated germ cells or somatic cells. Scale bar, 20 m.