THE MATERNAL STORE OF ZINC FINGER PROTEIN ENCODING MESSENGER-RNAS IN FULLY GROWN XENOPUS-OOCYTES IS NOT REQUIRED FOR EARLY EMBRYOGENESIS

A large family of C2H2 (Kruppel-like) zinc finger protein genes is maternally transcribed in Xenopus oocytes; many of the corresponding mRNAs are actively translated post-fertilization, before the onset of zygotic activation of transcription. With the aim of asking if any of these stored mRNAs have a function in Xenopus development, we made use of antisense oligonucleotide mediated, targeted RNA destruction. Injected oocytes lose the entire pool of C2H2 zinc finger protein encoding mRNAs. They are indistinguishable from control oocytes in their abilities to mature in vitro and to be fertilized in vitro. Embryos generated from such oocytes develop normally until tadpole stage. These findings do not rule out the possibility that C2H2 zinc finger protein genes are involved in developmental control in Xenopus. However, they do suggest that the biological function for at least some of the early expressed zinc finger proteins in Xenopus differs in important aspects from the way Kruppel or other DNA binding factors act as developmental regulators in Drosophila.