Role of riboswitches in gene regulation and their potential for algal biotechnology

Abstract

Riboswitches are regulatory elements in messenger RNA to which specific ligands can bind directly in the absence of proteins. Ligand binding alters the mRNA secondary structure, thereby affecting expression of the encoded protein. Riboswitches are widespread in prokaryotes, with over 20 different effector ligands known, including amino acids, cofactors and Mg2+ ions, and gene expression is generally regulated by affecting translation or termination of transcription. In plants, fungi and microalgae, riboswitches have been found, but only those bind thiamine pyrophosphate. These eukaryotic riboswitches operate through alternative splicing of the transcript, a highly conserved process. Here we review the current status of riboswitch research with specific emphasis on microalgae. We discuss new riboswitch discoveries and insights into the underlying mechanism of action, and how next generation sequencing technology provides the motivation and opportunity to improve our understanding of these rare but important regulatory elements. We also highlight the potential of microalgal riboswitches as a tool for synthetic biology and industrial biotechnology.