Histone H1 and transcriptionally active chromatin regions

A. A. Karavanov

doi:10.7124/bc.000021

Site-specific ubiquitylation acts as a regulator of linker histone H1

Nature Communications ◽

10.1038/s41467-021-23636-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Eva Höllmüller ◽

Simon Geigges ◽

Marie L. Niedermeier ◽

Kai-Michael Kammer ◽

Simon M. Kienle ◽

...

Keyword(s):

Posttranslational Modifications ◽

Histone H1 ◽

Linker Histone ◽

Active Chromatin ◽

Site Specific ◽

Linker Histone H1 ◽

Fundamental Process ◽

Core Histones ◽

Wide Scale

AbstractDecoding the role of histone posttranslational modifications (PTMs) is key to understand the fundamental process of epigenetic regulation. This is well studied for PTMs of core histones but not for linker histone H1 in general and its ubiquitylation in particular due to a lack of proper tools. Here, we report on the chemical synthesis of site-specifically mono-ubiquitylated H1.2 and identify its ubiquitin-dependent interactome on a proteome-wide scale. We show that site-specific ubiquitylation of H1 at position K64 modulates interactions with deubiquitylating enzymes and the deacetylase SIRT1. Moreover, it affects H1-dependent chromatosome assembly and phase separation resulting in a more open chromatosome conformation generally associated with a transcriptionally active chromatin state. In summary, we propose that site-specific ubiquitylation plays a general regulatory role for linker histone H1.

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Prothymosin α is a chromatin-remodelling protein in mammalian cells

Biochemical Journal ◽

10.1042/bj3330001 ◽

1998 ◽

Vol 333 (1) ◽

pp. 1-3 ◽

Cited By ~ 61

Author(s):

Jaime GÓMEZ-MÁRQUEZ ◽

Pilar RODRÍGUEZ

Keyword(s):

Mammalian Cells ◽

Nuclear Protein ◽

Nuclease Activity ◽

Histone H1 ◽

Micrococcal Nuclease ◽

Active Chromatin ◽

Dna Ladder ◽

Prothymosin Α ◽

Histone Octamer ◽

Dna Fragment

Prothymosin α (ProTα) is an abundant mammalian acidic nuclear protein whose expression is related to cell proliferation. Here we report that in HL-60 cells overexpressing ProTα, the accessibility of micrococcal nuclease to chromatin is strongly increased. In the DNA ladder generated by the nuclease activity, the sizes of the mononucleosome (146 bp, the DNA fragment that is bound to the histone octamer) and its multimers correspond to nucleosomes lacking histone H1. The percentage of histone-H1-depleted chromatin (active chromatin) is also higher in the cells overexpressing ProTα. On the basis of these and previous findings, we propose a biological role for ProTα in the remodelling of chromatin fibres through its interaction with histone H1.

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