We performed tissue-specific knockdown of those fly genes (155 RNAi stocks) by using two germline and two somatic GAL4 drivers: nos-GAL4 for germline cells from embryonic stage 9 onward, germline stem cells (GSC), and spermatogonia, bam-GAL4 for late spermatogonia and early spermatocytes, ptc-GAL4 for cyst stem cells and cyst cells, and upd-GAL4 for hub cells. The gene discussed is LGALS4; the disease is cyst.