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Theory of Living Matter Group

 

2nd Pub tutorial

Registration:
No registration required.

Date:
Wednesday, 18th March 2015, 6pm

Venue:
The Brew House, top floor
1 King St, Cambridge CB1 1LH

Catering:

As usual, snacks are provided by TLM, drinks can be bought in the pub.


“Why DNA?”

Andrew Travers, MRC Laboratory of Molecular Biology

The proposal of a double-helical structure for DNA over 60 years ago provided an eminently satisfying explanation for the heritability of genetic information. But why is DNA, and not RNA, now the dominant biological information store? I argue that, in addition to its coding function, the ability of DNA, unlike RNA, to adopt a B-DNA structure confers advantages both for information accessibility and for packaging. The information encoded by DNA is both digital - the precise base sequence specifying, for example, aminoacid sequences - and analogue. The latter determines the sequence-dependent physicochemical properties of DNA, for example its stiffness and susceptibility to strand separation. Most importantly DNA chirality enables the formation of supercoiling under torsional stress. I review recent experimental evidence suggesting that DNA supercoiling, especially that generated by DNA translocases, is a major driver of gene regulation and patterns of chromosomal gene organisation, and in its guise as a promoter of DNA packaging enables DNA to act as an energy store to facilitate the passage of translocating enzymes such as RNA polymerase.

“Building a DNA sandcastle: developing a granular model to describe large scale chromatin structure and dynamics”

Christopher Verstreken, Department of Physics and Stem Cell Institute

Aiming to determine the conformation of chromatin on a global scale, this is a computational model that approaches the nucleus as a system of independent yet interacting domains, similar to grains of sand. The mechanical behaviour of a nucleus under compression could therefore provide information about its structure and dynamics.