Email updates

Keep up to date with the latest news and content from Genome Biology and BioMed Central.

Open Badges Research news

Sir silencing

Jonathan B Weitzman

Genome Biology 2001, 2:spotlight-20010126-02  doi:10.1186/gb-spotlight-20010126-02

The electronic version of this article is the complete one and can be found online at:

Published:26 January 2001

© 2001 BioMed Central Ltd

Research news

Chromatin silencing depends on passage through the S-phase of the cell cycle and was widely believed to depend on DNA replication. In two papers in the January 26 Science, Kirchmaier and Rine and Li et al. challenge this dogma by reporting that the establishment of transcriptional silencing can occur in the absence of replication (Science 2001, 291:646-650; Science 2001, 291:650-653). Both groups used an ingenious genetic trick, involving site-specific recombination, to generate non-replicating DNA rings containing the silent HMR mating-type locus from budding yeast. Recruiting the silencing protein Sir1 induced silencing at the synthetic silencer without any detectable DNA replication. Furthermore, the authors show that the artificial silent rings mimic features of authentic heterochromatin, including histone hypoacetylation and altered supercoiling. Strangely, despite being independent of replication, silencing still required passage through the S-phase of the cell cycle.


  1. Silencing and heritable domains of gene expression.

    PubMed Abstract OpenURL

  2. [] webcite


  3. Cloning and characterization of four SIR genes of Saccharomyces cerevisiae.

    PubMed Abstract OpenURL