How a female X chromosome is inactivated
A team of researchers lead by Anton Wutz, Professor of Genetics at ETH Zurich, have now discovered several of these inactivation molecules. Virus insertions that destroyed a gene, which was required for Xist RNA to inactivate the X chromosome, the X chromosome was not inactivated, and the corresponding cells survived. In other experiments, ETH researchers were able to show that if a mouse cell lacks the Spen gene, the proteins responsible for altering chromosome structure are not able to accumulate as efficiently at the X chromosome. ETH Professor Wutz explains that further research is required to understand exactly how this mechanism works and what role the other recently discovered genes play in it. A few years ago, a team of French researchers postulated that, in addition to Xist, humans also have another system which ensures that the single X chromosome in men and one of the two X chromosomes in women remain active.