A new mode of action for the Rett Syndrome gene

I've written about Rett Syndrome for a few years now (a few examples here, here and here). Rett is a rare neurological disorder that primarily affects girls, and shares some features of autism. Although symptoms vary in type and severity, the disorder is marked by a progressive loss of speech and motor skills. Girls with Rett may also have seizures and trouble breathing.

In 1999, scientists found that mutations in a single gene, MECP2, cause Rett. You might think that a single-gene disorder would be easier to understand and eventually cure compared with more genetically complex disorders like autism. Maybe that's true. But researchers are still trying to find out what the MeCP2 protein does.

In the early 90s, Adrian Bird’s group purified MeCP2—which stands for methyl-CpG binding protein 2—and named the protein for its ability to bind parts of the DNA with a chemical tag called a methyl. Methyls tend to dampen the expression of genes, suggesting that MeCP2’s function is to silence genes.

Studies published since then suggest MeCP2 activates or represses the expression of many genes. Other results suggest that the protein binds throughout the genome, influencing the way DNA packs into a cell.

New evidence, published today (December 21) in Cell, shows that MeCP2 binds to spots throughout the genome that are tagged with the chemical, 5-hydroxymethylcytosine (5hmC) in mice, and that this interaction may be important for understanding Rett Syndrome.

See the rest of my story at the Rett Syndrome Research Trust blog, as well as a podcast by RSRT director Monica Coenraads.