MIT researchers have developed a new way to study the function of microRNA, tiny strands of genetic material that help regulate at least 25 percent of a cell's genes.

New research shows how a particular small molecule blocks the activity of a cancer-suppressing gene, allowing liver-cancer cells to grow and spread.

In the Aug. 1 issue of G&D, a team of Japanese scientists led by Dr. Shigeyuki Yokoyama (RIKEN and the University of Tokyo), presents heretofore the most relevant experimental system of microRNA-mediated translational repression.

MicroRNAs became the stars of the RNA universe when, in 2001, scientists found that these short RNAs can control whether or not genes are expressed. This month, scientists at Rockefeller University and the Wellcome Trust cast new light on the genesis of these key biological regulators and how they carry out their function.

While most RNAs work to create, package, and transfer proteins as determined by the cell’s immediate needs, miniature pieces of RNA, called microRNAs (miRNAs) regulate gene expression. Recently, researchers from the University of Pennsylvania School of Medicine determined how miRNAs team up with a regulatory protein to halt protein production. Results of the study were published recently in Cell.

During flowering four different types of floral organs need to be formed: sepals, which protect the inner organs; the frequently ornamental petals; stamens, which produce pollen and the carpels. This process is orchestrated by a large number of genes. Scientists at the Max Planck Institute for Plant Breeding Research in Köln (Germany) found, in cooperation with colleagues in Nijmegen (Netherlands) that a small molecule, a so-called microRNA, is crucial for the control of floral organs identity

Over 30% of our genes are under the control of small molecules called microRNAs. They prevent specific genes from being turned into protein and regulate many crucial processes like cell division and development, but how they do so has remained unclear. Now researchers from the European Molecular Biology Laboratory [EMBL] have developed a new method that uncovered the mode of action of microRNAs in a test tube.

In the May 15th issue of Genes & Development, an international collaboration of researchers, led by Dr. Yijun Qi (National Institute of Biological Sciences, China), report on their discovery of microRNAs in the unicellular green alga, Chlamydomonas reinhardtii. This is the first finding of microRNAs in a unicellular organism.

A role for a microRNA in the immune system has been shown by study of one of the world's first microRNA knockout mouse, reported Friday 27 April in Science. The microRNA acts as a lynchpin to balance the response of immune defences and the researchers suggest the corresponding human gene will have a similar vital role.

In the May 1st issue of G&D, Drs. Yong Sun Lee and Anindya Dutta (UVA) reveal that microRNAs can function as tumor suppressors in vitro.

Researchers at the Gladstone Institute of Cardiovascular Disease (GICD) announced they have identified a critical genetic factor in the control of many aspects of heart form and function. As reported in the journal Cell, scientists in the lab of Deepak Srivastava, MD, have successfully deleted a genetic factor, called a microRNA, in animal models to understand the role it plays in cardiovascular differentiation and development.