Xenopus laevis miRNA expression at different stages of development. Xenopus laevis

MicroRNAs (miRNAs) are involved in controlling various mechanisms during development by regulating gene expression at the post-transcriptional level. Many are highly conserved amongst diverse organisms and have highly specific spatio-temporal expression patterns during embryonic development. miRNAs are short, non-coding RNAs around 22 nucleotides long. They inhibit gene expression either by translational repression or by causing the degradation of the mRNAs they bind to.We have determined the expression patterns of 190 miRNAs in Xenopus laevis embryos using LNA oligonucleotides. In addition we have carried out small RNA-seq on different stages of early Xenopus development and have characterized the expression of 6 new miRNAs. In our analyses we have identified miRNA expression in many organs of the developing embryo suggesting important roles for these miRNAs in development. In particular a large number are expressed in neural tissue and in the somites. Surprisingly none of the miRNAs we have looked at show expression in the heart. Our results have been made freely available as a resource in both XenMark and Xenbase.