Friday, July 21, 2006
DNA - the long, thin molecule that carries our hereditary material - is compressed around protein scaffolding in the cell nucleus into tiny spheres called nucleosomes. The bead-like nucleosomes are strung along the entire chromosome, which is itself folded and packaged to fit into the nucleus. What determines how, when and where a nucleosome will be positioned along the DNA sequence?
Dr. Eran Segal and research student Yair Field of the Computer Science and Applied Mathematics Department at the Weizmann Institute of Science have succeeded, together with colleagues from Northwestern University in Chicago, in cracking the genetic code that sets the rules for where on the DNA strand the nucleosomes will be situated. Their findings appeared today in Nature.
The precise location of the nucleosomes along the DNA is known to play an important role in the cell's day to day function, since access to DNA wrapped in a nucleosome is blocked for many proteins, including those responsible for some of life's most basic processes. Among these barred proteins are factors that initiate DNA replication, transcription (the transfer of genetic information from DNA to RNA) and DNA repair.