Fig. 2.

Inhibition of Y RNA function is embryonic lethal after the midblastula transition in Xenopus laevis. (A) Phenotypes of developing Xenopus laevis embryos after microinjection of xY RNA-specific MOs. The indicated MOs (100 ng/embryo) were injected at stage 1, and representative embryos were photographed at the indicated stages. Black panels indicate that corresponding embryos had died and disintegrated by that stage. (B) Dose-dependent and additive lethal defects after comicroinjection of different xY RNA-specific antisense MOs. The indicated MOs (50 ng plus 50 μg/embryo) were microinjected at stage 1, and representative embryos were analyzed as described above. All embryos developed normally until stage 8.5. (C) Inhibition of xY RNA function does not affect zygotic transcription at the midblastula transition. Embryos were injected at stage 1 and harvested before MBT, when control embryos had reached stage 4, and after MBT, when control embryos had reached stage 9. Expression levels of GS17, histone H1, ORC2, and MCM3 mRNAs were determined by qRT-PCR relative to ODC mRNA.