Genome under surveillance

摘要

Decoding the information stored in DNA requires an intricate balance between processes that turn gene expression on or off. A protein that influences the packaging of DNA regulates this balance genome-wide. Organisms store instructions for their own existence in DNA. Specific proteins access and read the DNA sequence either to replicate it or to mediate gene expression. But this DNA-reading process is impeded by chromatin — tight packages of DNA and histone proteins that are essential for nuclear compartmen-talization of the genome. Strategies for opening chromatin are therefore crucial for basic molecular processes such as gene transcription; this is not to say that restricting access to the genome is less important. On page 1031 of this issue, Whitehouse et al. describe an elegant chromatin-based mechanism by which yeast (Saccharomyces cerevisiae) cells prevent inappropriate transcription.