Conservation of the sequence and temporal expression of let-7 heterochronic regulatory RNA

摘要: Two small RNAs regulate the timing of Caenorhabditis elegans development. Transition from first to second larval stage fates requires 22-nucleotide lin-4 RNA and transition late adult cell 21-nucleotide let-7 RNA. The genes are not homologous each other, but complementary sequences in 3' untranslated regions a set protein-coding target that normally negatively regulated by RNAs. Here we have detected ~21 nucleotides samples wide range animal species, including vertebrate, ascidian, hemichordate, mollusc, annelid arthropod, several cnidarian poriferan Saccharomyces cerevisiae, Escherichia coli or Arabidopsis. We did detect these species. found temporal regulation is also conserved: expression at stages C. Drosophila , 48 hours after fertilization zebrafish, annelids molluscs. regulatory may control transitions during development across phylogeny.