Nonsense-mediated mRNA decay in Xenopus oocytes and embryos.

Mutant mRNAs carrying a premature stop codon have a reduced half-life in the cells of many species, probably due to the presence of "surveillance" pathways, which selectively target such mRNAs for degradation. It is reported here that this phenomenon may also occur in Xenopus. In vitro-synthesised transcripts encoding a Xenopus POU-domain protein, XLPOU-60, are stable after injection into the oocyte and embryo. However, introduction of a premature stop codon into these transcripts results in their rapid degradation following injection. In contrast, mutant transcripts with additional or deleted codons but retaining a correct reading frame are stable. These results suggest that RNA stability should be considered when designing control mRNAs for Xenopus injection experiments.