Theory Lunch this week
July 27, 2011 § Leave a comment
Assembly and action of multiprotein complexes on chromatin
29 July 2011, 12–1.30 pm, Warren Alpert 563
DKFZ German Cancer Research Center in the Helmholtz Association
The macromolecular machineries of DNA transcription, replication and repair form from individual components at specific chromatin sites. Assembly is usually depicted as the step-wise and ordered incorporation of building blocks. Here I will report on our imaging of a DNA repair pathway in living cells that has forced us to develop an alternative picture: The assembly of a complex is an essentially unordered process, with building blocks binding and dissociating continuously. An ordered sequence of molecular events emerges from cycles of complex formation and enzymatic action. This model has obvious parallels with signal-transduction schemes. I will discuss consequences of the model for the specificity and rate of DNA repair (along with some experimental tests) and speculate on more general rules for the assembly and action of macromolecular complexes on chromatin.