Enhanced ciliogenesis and double bubble-mutant rescue by inhibition of Jagged/Notch signaling. (A) Wild-type double bubble (dbb) heterozygotes viewed in confocal projections show alternating thick acetylated tubulin-positive bundles of cilia (arrowheads) in pronephric lumens (individual tubules are marked with asterisks in A-D).(B) jagged 2 exon 20-morpholino injection results in enhanced ciliogenesis, seen here in a single pronephric tubule with a slightly expanded lumen. (C) A single dbb-mutant pronephric lumen showing lossor shortening of cilia bundles (arrowheads), and a grossly dilated lumen(*). (D) dbb-mutant homozygotes injected with jagged 2 exon 20 morpholino recover normal tubule morphology (paired tubules marked with asterisks) and show a dramatic recovery of ciliogenesis.(E) dbb-mutant homozygote at 2.5 dpf showing bilateral cyst formation in the proximal pronephros (arrow). (F) dbb-mutant homozygote injected with jagged 2 exon 20 morpholino at the one-cellstage, showing the absence of cyst formation (arrow; mutant rescue).(G) Histological section of dbb-homozygote pronephros showing a cystic pronephric tubule (*), dilated pronephric tubules (arrow)and edema (#). (H) Histological section of a dbb homozygote injected with jagged 2 exon 20 morpholino at the one-cell stage,showing complete absence of cystic pathology and edema (arrow,wild-type-appearing pronephric tubules; *, normal glomerular structure). (I) Control DMSO-treated dbb-mutant embryo showing cystic proximal pronephros (*). (J) DAPT treatment (100µM started at 9.5 hpf) of dbb homozygotes eliminates cystic distension of the pronephros (*, glomerulus; arrow, pronephric tubule). In these experiments, dbb homozygotes were identified independently of cyst formation by the characteristic mutant ventral axis curvature in 25% of embryos from heterozygote pair matings.