Fig. 7. GAGs are not required in the ovarian follicle cell layer for embryonic DV polarity. The technique of Nilson and Schüpbach (Nilson and Schüpbach, 1998) was used to generate marked mutant follicle cells whose position in the follicle layer could be determined by their altered chorion imprints. In all cases shown, mutant clones were located ventrally in the follicle cell layer, and are identifiable by the more transparent appearance of the chorion imprints in comparison to those made by wild-type cells. (A,B) Ventral clones of pipe mutant cells led to the production of embryos that were partially dorsalized, as indicated by the tail-up phenotype (A,B) and the narrow ventral denticle bands (A). By contrast, ventral follicle cells mutant for papss (C), sgl (D), sfl (E) and frc (F) did not lead to the production of dorsalized embryos.