The ERM-1 membrane-binding domain directs erm-1 mRNA localization to the plasma membrane in the C. elegans embryo.

Abstract

mRNA localization and transport are integral in regulating gene expression. In Caenorhabditis elegans embryos, the maternally inherited mRNA erm-1 (Ezrin/Radixin/Moesin) becomes concentrated in anterior blastomeres. erm-1 mRNA localizes within those blastomeres to the plasma membrane where the essential ERM-1 protein, a membrane-actin linker, is also found. We demonstrate that the localization of erm-1 mRNA to the plasma membrane is translation dependent and requires its encoded N-terminal, membrane-binding (FERM) domain. By perturbing translation through multiple methods, we found that erm-1 mRNA localization at the plasma membrane persisted only if the nascent peptide remained in complex with the translating mRNA. Indeed, re-coding the erm-1 mRNA coding sequence while preserving the encoded amino acid sequence did not disrupt erm-1 mRNA localization, corroborating that the information directing mRNA localization resides within its membrane-binding protein domain. A single-molecule inexpensive fluorescence in situ hybridization screen of 17 genes encoding similar membrane-binding domains identified three plasma membrane-localized mRNAs in the early embryo. Ten additional transcripts showed potential membrane localization later in development. These findings point to a translation-dependent pathway for localization of mRNAs encoding membrane-associated proteins.