University of Warwick physicist Dr Mario Nicodemi, has recently published research on just how one X chromosome is able to silence another as part of the XCI process. However for that stage in the process to happen the X chromosomes have to quickly pair off (colocalization) in a way that allows each part of those pairs of X chromosomes to be very close together and aligned in a particular way.
In this latest paper the Warwick and Naples researchers looked at a particular "DNA specific binding molecule" including a protein known as CTCF that seemed to play a role in pairing off of X chromosomes. In the past when other researchers had mutated CTCF, or deleted the sections of DNA that the CTCF bound to, they found that it disrupted the pairing up or colocalization of the X Chromosomes. Clearly then CTCF had a role to play in the process but it was not obvious how it did so with the precise timing and speed required.
Obviously sheer chance meant that CTCFs would randomly encounter and bind to an X chromosome. There was an even smaller probability then that such a pairing would then encounter another X chromosome and bind to it as well the CTCF would effectively then force colocalization by this unlikely double chance encounter, forming a chemical bridge between the two chromosomes. However such a gradual chance based occurrence did not fit with the speed and efficiency of how the actual process of colocalization of the X chromosomes really happened during XCI.
The Warwick lead research team created a model of the interaction between X chromosomes and CTCF proteins using polymer physics. They looked at models of chains of polymer beads that had almost the same number of chemical binding s
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| Contact: Dr Mario Nicodemi M.Nicodemi@warwick.ac.uk 39-333-899-5996 University of Warwick Source:Eurekalert |