Maintenance of Stable Heterochromatin Domains by Dynamic HP1 Binding

See allHide authors and affiliations

Science  31 Jan 2003:
Vol. 299, Issue 5607, pp. 721-725
DOI: 10.1126/science.1078572

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution


One function of heterochromatin is the epigenetic silencing by sequestration of genes into transcriptionally repressed nuclear neighborhoods. Heterochromatin protein 1 (HP1) is a major component of heterochromatin and thus is a candidate for establishing and maintaining the transcriptionally repressive heterochromatin structure. Here we demonstrate that maintenance of stable heterochromatin domains in living cells involves the transient binding and dynamic exchange of HP1 from chromatin. HP1 exchange kinetics correlate with the condensation level of chromatin and are dependent on the histone methyltransferase Suv39h. The chromodomain and the chromoshadow domain of HP1 are both required for binding to native chromatin in vivo, but they contribute differentially to binding in euchromatin and heterochromatin. These data argue against HP1 repression of transcription by formation of static, higher order oligomeric networks but support a dynamic competition model, and they demonstrate that heterochromatin is accessible to regulatory factors.

  • * To whom correspondence should be addressed. E-mail: mistelit{at}

View Full Text

Stay Connected to Science