MicroRNAs have emerged as important master regulators in cells, since each one can shut down several target genes. Riding on top of the master regulators is Drosha, the RNA-cutting enzyme that initiates microRNA processing in the nucleus. Drosha and its relative Dicer have been attracting attention in cancer biology, because they are thought to be behind a phenomenon where cancerous cells can “infect†their healthy neighbors via tiny membrane-clothed packets called exosomes.
At Emory, pharmacologist Zixu Mao and colleagues recently published in Molecular Cell their findings that Drosha is regulated by stress (experimentally: heat or peroxide) through p38 MAP kinase.
Although we mention relevance to cancer above, this is one of those basic cell biology findings that may have applicability to several areas of medicine. Alterations in miRNA processing have been linked to neurodegenerative disease (Fragile X-associated tremor/ataxia syndrome, for one example). MicroRNA-packed exosomes are also being studied by biomedical engineers as potential therapeutic tools in regenerative medicine, so knowing what cellular stress does to miRNA production could be useful. Read more