LGALS4 and cyst: Two drivers, tj-GAL4 expressed in somatic cyst stem cells and cyst cells (analogous to mammalian Sertoli cells) and nos-GAL4 expressed in early germline cells (including germ stem cells), were used to achieve the cell-specific knockdown of Caf1-55 in Drosophila testis (Supplemental Figure 5, B and C, and Supplemental Figure 6, A and B).