Do the charges matter?-balancing the charges of the chromodomain proteins on the nucleosome.

Kyoko Hiragami-Hamada,Jun-Ichi Nakayama

doi:10.1093/jb/mvz004

Kyoko Hiragami-Hamada, Jun-Ichi Nakayama

Open Access

https://doi.org/10.1093/jb/mvz004

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Abstract

The chromodomain (CD) is a member of the Royal family of conserved chromatin-binding motifs with methylated substrate binding ability, and is often found in ‘readers’ or ‘writers’ of repressive histone marks. The regions upstream or downstream of the CD are generally highly charged. Several previous studies suggested that these charged regions modulate the CD’s chromatin-binding activity. Considering the relatively weak interaction between the CD and a modified histone tail, it is puzzling how the highly charged CD-flanking regions are ‘balanced’ on the highly charged nucleosomes to mediate a modification-dependent interaction. Interestingly, the charge distributions along the CD and surrounding regions appear to be distinct among different types of readers and writers, indicating their functional relevance. Here, we describe and discuss the current understanding of the highly charged CD-flanking regions and the potential experimental concerns caused by the regions.

Highlights

Our genetic information is stored and regulated in the form of chromatin, a large, sophisticated multimeric complex composed of DNA, RNA and proteins
The basic repeating structural and regulatory unit of chromatin is the nucleosome, which consists of 147 bp of DNA wrapped around a core histone octamer [1]
Each core histone possesses an N-terminal tail that extends from the nucleosome core

Summary

Introduction

Our genetic information is stored and regulated in the form of chromatin, a large, sophisticated multimeric complex composed of DNA, RNA and proteins. The opposite charges on histone tails and DNA and their modulation have a considerable impact on chromatin structure. The HP1-type methyl H3K9 reader proteins generally possess an acidic N-terminal region, an acidic-neutral globular CD, and a highly basic C-terminal hinge region.

Results

Conclusion