Inferring microRNA function and evolution from thousands of mRNA expression profiles

1. Seminario Institucional LANGEBIO Inferring microRNA function and evolution from thousands of mRNA expression profiles Ponente: Dr. Cei AbreuGoodger LANGEBIO Laboratorio de Genómica Computacional de RNA cei@langebio.cinvestav.mx Martes 12 de Abril 10:00 am AUDITORIO LANGEBIO

2. Initially thought to be a genetic peculiarity of C. elegans, microRNAs (miRNAs) are now known to be one of the most extensive families of gene regulators, with vertebrate genomes encoding hundreds of distinct miRNAs. They post-transcriptionally regulate their target genes by binding to the 3’ un-translated regions (3’UTR) leading to transcript destabilization. Since animal miRNAs can repress hundreds of target genes, messenger RNA expression profiles can be used to predict which miRNAs are differentially expressed across the conditions under study. I will talk about a comprehensive analysis of microarray experiments that we are conducting. Thousands of expression profiles were obtained from ten different species, including experiments designed to compare tissues, cell lines, diseases, clinical treatments, developmental stages and genetic modifications. We processed these in search of miRNA signatures using Sylamer, a tool that we developed for this purpose. Gene Set Enrichment Analysis was used to add annotation to each experiment, allowing us to assign general functions to miRNAs. Even after correcting for biases due to the abundance and redundancy of different types of experiment, miRNAs tend to be associated firstly with particular tissues, and secondly to developmental stages. These signatures are caused by ancient miRNAs that are conserved both in sequence and expression patterns as far back as the origin of the Bilateria. Finally, we find that our analysis of expression profiles can be used to predict miRNA targets that are functionally conserved. Abstract