Translational Co-Regulation of a Ligand and Inhibitor by a Conserved RNA Element

Nucleic Acids Res. 2018 Jan 9;46(1):104-119. doi: 10.1093/nar/gkx938.

Abstract

In many organisms, transcriptional and post-transcriptional regulation of components of pathways or processes has been reported. However, to date, there are few reports of translational co-regulation of multiple components of a developmental signaling pathway. Here, we show that an RNA element which we previously identified as a dorsal localization element (DLE) in the 3'UTR of zebrafish nodal-related1/squint (ndr1/sqt) ligand mRNA, is shared by the related ligand nodal-related2/cyclops (ndr2/cyc) and the nodal inhibitors, lefty1 (lft1) and lefty2 mRNAs. We investigated the activity of the DLEs through functional assays in live zebrafish embryos. The lft1 DLE localizes fluorescently labeled RNA similarly to the ndr1/sqt DLE. Similar to the ndr1/sqt 3'UTR, the lft1 and lft2 3'UTRs are bound by the RNA-binding protein (RBP) and translational repressor, Y-box binding protein 1 (Ybx1), whereas deletions in the DLE abolish binding to Ybx1. Analysis of zebrafish ybx1 mutants shows that Ybx1 represses lefty1 translation in embryos. CRISPR/Cas9-mediated inactivation of human YBX1 also results in human NODAL translational de-repression, suggesting broader conservation of the DLE RNA element/Ybx1 RBP module in regulation of Nodal signaling. Our findings demonstrate translational co-regulation of components of a signaling pathway by an RNA element conserved in both sequence and structure and an RBP, revealing a 'translational regulon'.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions / genetics
  • Animals
  • Embryo, Nonmammalian / embryology
  • Embryo, Nonmammalian / metabolism*
  • Gene Expression Regulation, Developmental*
  • HEK293 Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Left-Right Determination Factors / genetics
  • Left-Right Determination Factors / metabolism
  • Ligands
  • Nodal Signaling Ligands / genetics
  • Nodal Signaling Ligands / metabolism
  • RNA / genetics
  • RNA / metabolism
  • Zebrafish / embryology
  • Zebrafish / genetics*
  • Zebrafish / metabolism
  • Zebrafish Proteins / genetics*
  • Zebrafish Proteins / metabolism

Substances

  • 3' Untranslated Regions
  • Intracellular Signaling Peptides and Proteins
  • Left-Right Determination Factors
  • Lft2 protein, zebrafish
  • Ligands
  • Nodal Signaling Ligands
  • Zebrafish Proteins
  • lft1 protein, zebrafish
  • ndr1 protein, zebrafish
  • ndr2 protein, zebrafish
  • RNA