Book of Abstracts: Albany 2009

category image Albany 2009
Conversation 16
June 16-20 2009
© Adenine Press (2008)

On the Structure of The 30 nm Chromatin Fibre

DNA is packed as chromatin on several levels in the eukaryotic nucleus. Dissection of chromatin with nucleases produces three stable substructures: the nucleosome core particle, the chromatosome and the 30 nm fibre. Whilst the first two allow transcription, the 30 nm fibre is taken to be the first level of transcriptionally dormant chromatin and it has an important functional role in cell differentiation and epigenetic regulation. Its structure has been a subject of continuing discussion since native fibres cannot readily be crystallized. This problem has recently been addressed by reconstitution of fibres on repeats of DNA sequences having nucleosome-positioning properties and two different structures were reported.(1,2). The reconstitution results and their interpretations are compared with experimental data from native chromatin and it is shown that the results of Robinson et al.(2) conform well with the known structural features of native fibres and are a good first step towards understanding the structure of the fibre.

References and Footnotes
  1. Dorigo B, Schalch T, Kulangara A, Duda S, Schroeder RR, et al. 2004. Nucleosome arrays reveal the two-start organization of the chromatin fiber. Science 306, 1571?1573.
  2. Robinson PJ, Fairall L, Huynh VA, Rhodes D. 2006. EM measurements define the dimensions of the ??30-nm?? chromatin fiber: evidence for a compact, interdigitated structure. Proc Natl Acad Sci USA 103, 6506?6511.

D. Staynov

Imperial College London
Guy Scadding Building
Dovehouse St.
London SW3 6LY UK

d.staynov@imperial.ac.uk donchyana@btinternet.com