Overexpression of timp in the somatic component of otherwise wild-type ovaries using a UASt-timp insertion [28] combined with either a heat-shock Gal4 or the germarium-specific Gal4 c587 [29] resulted in the formation of compound follicles containing more than one germline cyst (Fig 3A and 3B). The gene discussed is TIMP1; the disease is cyst.