Insulators are fundamental components of the eukaryotic genomes

doi:doi:10.1038/sj.hdy.6800669

Heredity (2005) 94, 571–576. doi:10.1038/sj.hdy.6800669 Published online 6 April 2005

Insulators are fundamental components of the eukaryotic genomes

E Brasset¹ and C Vaury¹

¹INSERM U384, Faculté de Médecine, BP38, Clermont-Ferrand 63001, France

Correspondence: C Vaury, INSERM U384, Faculté de Médecine, 28 Place H. Dunant, BP38, Clermont-Ferrand 63001, France. E-mail: Chantal.VAURY@inserm.u-clermont1.fr

Received 22 November 2004; Accepted 17 February 2005; Published online 6 April 2005.

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Abstract

The properties of cis-regulatory elements able to influence gene transcription over large distances have led to the hypothesis that elements called insulators should exist to limit the action of enhancers and silencers. During the last decades, insulators have been identified in many eukaryotes from yeast to human. Insulators possess two main properties: (i) they can block enhancer–promoter communication ('enhancer blocker activity'), and (ii) they can prevent the spread of repressive chromatin ('barrier activity'). This review focuses on recent studies designed to elucidate the molecular mechanisms of the insulator function, and gives an overview of the critical role of insulators in nuclear organization and functional identity of chromatin.