Small non-coding RNAs in animal development

Key Points The functional roles of small non-coding RNAs in vertebrates are beginning to be elucidated thanks to specific gene-deletion approaches. miR-15, miR-16 and miR-430 are involved in modulation of the Nodal signalling pathway in different phases of vertebrate embryonic development. miR-124 contributes to the adoption of neural cell fate by regulating the switch between PTB and nPTB, two regulators of alternative splicing. miR-208 deletion results in a failure to produce cardiac hypertrophy in response to various stresses. miR-181 and miR-155 have a complex regulatory role in lymphocyte maturation and the immune response. piRNAs are a novel class of small non-coding RNAs that are expressed in the germline, and that are possibly involved in inhibiting the mobilization of transposons. Our understanding of the biological functions of small non-coding RNAs has been fostered by the analysis of genetic deletions of individual microRNAs (miRNAs) in mammals. These studies show that miRNAs are key regulators of animal development and are potential human disease loci. The modulation of gene expression by small non-coding RNAs is a recently discovered level of gene regulation in animals and plants. In particular, microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs) have been implicated in various aspects of animal development, such as neuronal, muscle and germline development. During the past year, an improved understanding of the biological functions of small non-coding RNAs has been fostered by the analysis of genetic deletions of individual miRNAs in mammals. These studies show that miRNAs are key regulators of animal development and are potential human disease loci.