Flies bearing homozygous or trans-heterozygous mutations in boid04197 and boie01708 exhibit excess follicle cells that accumulate between developing egg chambers. Although stalks of follicle cells between egg chambers in wild-type flies contain nine follicle cells on average, the mutant stalks have twice as many cells. Additional defects associated with excessive follicle cell production, including improper egg chamber packaging, delayed differentiation, and follicle cell polarity defects are also observed. Follicle stem cells (FSCs) in the mutants proliferate more frequently than in wild-type. The number of dividing pre-follicle cells derived from mutant FSCs is also higher than wild-type.
