Available online at www.sciencedirect.com Nucleus and gene expression Editorial overview Elisa Izaurralde and Phillip D Zamore Current Opinion in Cell Biology 2009, 21:331–334 Available online 14th May 2009 0955-0674/$ – see front matter # 2009 Elsevier Ltd. All rights reserved. DOI 10.1016/j.ceb.2009.04.013 Elisa Izaurralde That most information flows from DNA through RNA to protein remains the Department of Biochemistry, Max-Planck- organizing principle of modern molecular biology. Thus we begin this issue Institute for Developmental Biology, with an introduction to DNA replication by Mike O’Donnell and Nina Yao. Spemannstrasse 35, D-72076 Tu¨ bingen, Germany They describe the composition and function of the replisome, the machine e-mail:
[email protected] that organizes activities at the replication fork, highlighting the unique challenges solved in the evolution of DNA replication proteins. Not only Elisa Izaurralde leads the does the replisome coordinate DNA copying on the leading and lagging Department of Biochemistry at the strands, it also allows the replication apparatus to skip over DNA lesions and Max Planck Institute for to pass a transcribing RNA polymerase without interrupting either tran- Developmental Biology in Tu¨ bingen, scription or replication. Germany. Her research focuses on the molecular mechanisms that Initiating transcription at the right place, at the right time, and in the right regulate gene expression at the cells is, of course, the primary challenge of gene regulation. Timothy post-transcriptional level, with Sikorski and Stephen Buratowski identify a key paradox in initiating mRNA particular emphasis on mRNA transcription: a conserved set of transcription initiation proteins are used to surveillance, decay, and silencing in recruit a common RNA polymerase, RNA Pol II, to many different tran- scription initiation sequences (promoters).