On the other hand, a constitutively active form of Yan (YanCA), when expressed in cyst cells using the Tj-Gal4 driver, resulted in phenotypes similar to those observed in Tj>E(Pc) RNAi testes (Figs 1C, 2C and 2D, S3A, S3B and S3B’ Fig). The gene discussed is LGALS4; the disease is cyst.