Figure 7.

Loss of Pkd1 expression in zebrafish results in decreased jaw bone mineralization and tail curvature, which can be rescued with PC1-CTT or TAZ(S89A) overexpression. (A) Morpholinos corresponding to the zebrafish Pkd1a and Pkd1b PC1 or TAZ genes were injected into zebrafish embryos at the 1-2 cell stage to impair expression of the two Pkd1 genes and/or of TAZ. The embryos were subsequently injected with 300nM of mRNA encoding HA-PC1-CTT or TAZ(S89A), where indicated. At 7dpf the embryos were stained for calcified bone using the fluorescent calcein dye dissolved in deionized water, mounted in agarose and imaged. (B) Bone mineralization was quantified on Image-J using thresholded images. The data represent averages of three independent experiments (n = 40–100 embryos per condition); error bars represent standard error of the mean (SEM). (C and D) Morpholinos corresponding to the zebrafish Pkd1a and Pkd1b PC1 or TAZ genes were injected into zebrafish embryos at the 1–2 cell stage to impair expression of the two Pkd1 genes and/or of TAZ. The embryos were subsequently injected with 300nM of mRNA encoding HA-PC1-CTT or TAZ(S89A), where indicated. Images of embryos injected with Pkd1a/b morpholinos alone or followed by injected of mRNA encoding TAZ(S89A) are presented in Panel C. Tail curvature was scored and the results were binned into straight, mild, moderate and severe categories, as previously described (12). Knockdown of Pkd1a and Pkd1b produce a curly tail phenotype whose severity is partially ameliorated by expression of the PC1-CTT. Loss of TAZ expression prevents the PC1-CTT mediated rescue, but expression of TAZ(S89A) is sufficient to rescue the curly tail phenotype even in the absence of PC1-CTT expression.