Brain complexity: virus help (Introduction)

by David Turell , Thursday, January 22, 2015, 14:56 (3593 days ago) @ David Turell

Endogenous viruses in mouse brain are found to add complex functionality, and make up part of junk DNA:-"Our intimate relationship with these so-called endogenous retroviruses may be distressing to think about but a study published last week in Cell Reports suggests that they may help shape that thinking by participating in brain development. By manipulating mice genetics, researchers found evidence that some endogenous retroviruses gained new roles that are important for brain development in our not-so-distant rodent relatives. “Brain cells are very complex compared to other cells,” says Johan Jakobsson, a researcher at Lund University in Sweden and lead author of the study. “Co-opting endogenous retroviruses allows for much more complexity, especially since they make up so much of the genome.”-"Most endogenous retroviruses serve a life sentence, and are essentially permanently locked down via a gene-silencing process called DNA methylation. The study by Jakobsson and colleagues suggests that certain endogenous retroviruses don't serve such a harsh sentence and can get out on parole, so to speak, to carry out important developmental duties in the brains of mouse embryos.-"The parole officer in this situation is a protein called TRIM28, which has the ability to put the endogenous retroviruses back on lockdown by a more reversible gene-silencing process, called histone modification. After researchers knocked out TRIM28 in a variety of cells, including liver, brain and white blood cells, they noticed changes in mouse gene expression only in brain cells. “There seems to be a different mechanism regulating endogenous retroviruses in brain cells than in other cells,” Jakobsson says."-http://www.scientificamerican.com/article/ancient-viruses-gain-new-functions-in-the-brain/?WT.mc_id=SA_MB_20150121