The addition of two particular gene snippets to a skin cell’s usual genetic material is enough to turn that cell into a fully functional neuron, researchers from the Stanford University School of Medicine have found.

Scientists discovered two years ago that they could get similar results if they transformed the skin cell first into a stem cell and then coaxed the stem cell into becoming a neuron. Now researchers have found that it’s possible to go straight from skin cell to neuron. Short chains of genetic material called microRNA (which can bind to specific genetic transcripts to turn off their activity) were able to get the cells to switch.

The researchers discovered that two specific microRNAs, miR-9/9* and miR-124, trigger the switch by controlling a molecular machine (called the BAF chromatin remodeling complex) that shapes chromosomes so they’ll direct the cell to remain a stem cell. When the microRNAs bind to one subunit of this 13-membered complex, they turn this function off, and the cells begin to grow up and connect to one another — that is, they become mature, functioning neurons, the researchers said.

Ref.: Gerald R. Crabtree, et al., MicroRNA-mediated conversion of human fibroblasts to neurons, Nature, 2011; [DOI: 10.1038/nature10323]