Fig. 4.

Bicc1 is epistatic to Pkd2. (A-A″) Analysis of the expression of nbc-1 in the Xenopus late distal tubule at stage 39 by whole-mount in situ hybridization of uninjected control embryos, and embryos radially injected with xBicC-MO1+2 in the presence or absence of a single injection of 2 ng pkd2 mRNA. (B) Quantification of the expression of nbc-1 in the late distal tubule from the experiments shown in A-A″. Black, bilateral expression; white, no expression; gray, unilateral expression rescued by co-injected mRNA. The number of embryos analyzed is indicated. (C-D) Reciprocal experiments to those in A-B using Xenopus embryos injected with either Pkd2-MO alone or together with pkd2-myc or bicc1 mRNA. Co-injection with pkd2-myc rescued nbc-1 expression, whereas co-injection with bicc1 did not. (E) Flow diagram outlining the proposed mechanism of Bicc1 activity.