Fig. 5

Inhibition of HSP90 function increases cyclopia penetrance in Sqt-deficient embryos. (A–F) Phenotypes from MO knockdown of either HSP90A or HSP90B in WT and MZsqt^hi975/hi975 embryos. WT and MZsqt^hi975/hi975 embryos were injected with 2 ng of either control MO, HSP90A MO or HSP90B MO. All injected embryos were incubated overnight and scored for cyclopia on day 2. Apostrophes (′) indicate a frontal view of the same specimen. A variety of defects, including small heads, short axes and compressed, U-shaped somites were observed both in MZsqt and WT embryos (B, C, E, F). In addition, both HSP90A MO and HSP90B MO increased the incidence of cyclopia specifically in MZsqt, but not WT, embryos (E′, F′, G). (G) MO knockdown of either HSP90A or HSP90B increases the cyclopia rate in MZsqt^hi975/hi975 embryos. The number of WT embryos injected and scored for cyclopia as above were: Ctrl MO, n = 41; HSP90A MO, n = 35; HSP90B MO, n = 39. The MZsqt^hi975/hi975 embryo numbers were: Ctrl MO, n = 57; HSP90A MO, n = 60; HSP90B MO, n = 74. The observed differences in cyclopia rates had P < 0.001 and P = 0.001 chances of occurring randomly, for the HSP90A and HSP90B experiments, respectively. (H) HSP90-inhibitory drugs induce cyclopia in MZsqt^cz35/cz35 embryos. To test the effects of drugs inhibiting HSP90, WT and MZsqt^cz35/cz35 embryos were injected with radicicol (WT, n = 19; MZsqt, n = 19), geldanamycin (WT, n = 18; MZsqt, n = 46) or carrier buffer (DMSO) alone (WT, n = 19; MZsqt, n = 49). All injected embryos were incubated overnight and scored for cyclopia on day 2. The observed differences in cyclopia rates had P < 0.001 and P = 0.008 chances of occurring randomly, for the radicicol and geldanamaycin experiments, respectively.