Scientists announced this week the development of a new computational method that provides a reliable way to estimate the total number of miRNA genes in different animals. The researchers used the tool to help identify 88 miRNA genes in the worm C. elegans, a model system important in the study of human genetics. They also estimate that miRNA genes comprise nearly one percent of the human genome, making miRNA genes one of the more abundant types of regulatory genes in humans. The next step, say researchers, is to investigate the roles they play in cell growth and development.
This work, from David Bartel's lab at the Whitehead Institute for Biomedical Research and Christopher Burge's lab at MIT, was published in the April 13 issue of Genes and Development.
"MicroRNAs have been controlling the regulation of other genes for a very long time," said Bartel. "Having this extra layer of gene regulation may have enabled the emergence of the multicellular body plans found in both plants and animals. The developmental processes that give rise to an adult plant or animal require a lot of turning on and off of genes."
For many years, miRNAs went undetected because they do not code for proteins--the benchmark traditionally used to define genes within a genome. Interest in RNA as a gene regulator began when researchers first discovered two small RNAs that impacted the translation of genes into proteins in worms. If these RNAs were missing, a worm's development stalled before it reached maturity.