Asymmetric Localization of CK2? During Xenopus Oogenesis.

ABSTRACT: The establishment of the dorso-ventral axis is a fundamental process that occurs after fertilization. Dorsal axis specification in frogs starts immediately after fertilization, and depends upon activation of Wnt/?-catenin signaling. The protein kinase CK2? can modulate Wnt/?-catenin signaling and is necessary for dorsal axis specification in Xenopus laevis. Our previous experiments show that CK2? transcripts and protein are animally localized in embryos, overlapping the region where Wnt/?-catenin signaling is activated. Here we determined whether the animal localization of CK2? in the embryo is preceded by its localization in the oocyte. We found that CK2? transcripts were detected from stage I, their levels increased during oogenesis, and were animally localized as early as stage III. CK2? transcripts were translated during oogenesis and CK2? protein was localized to the animal hemisphere of stage VI oocytes. We cloned the CK2? 3'UTR and showed that the 2.8 kb CK2? transcript containing the 3'UTR was enriched during oogenesis. By injecting ectopic mRNAs, we demonstrated that both the coding and 3'UTR regions were necessary for proper CK2? transcript localization. This is the first report showing the involvement of coding and 3'UTR regions in animal transcript localization. Our findings demonstrate the pre-localization of CK2? transcript and thus, CK2? protein, in the oocyte. This may help restrict CK2? expression in preparation for dorsal axis specification.

SUBMITTER: Imbrie GA 

PROVIDER: S-EPMC4207361 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature