The H3 chaperone function of NASP is conserved in Arabidopsis

Abstract

Histones are abundant cellular proteins but, if not incorporated into chromatin, they are usually bound by histone chaperones. Here, we identify Arabidopsis NASP as a chaperone for histones H3.1 and H3.3. NASP interacts in vitro with monomeric H3.1 and H3.3 as well as with histone H3.1-H4 and H3.3-H4 dimers. However, NASP does not bind to monomeric H4. NASP shifts the equilibrium between histone dimers and tetramers towards tetramers but does not interact with tetramers in vitro. Arabidopsis NASP promotes [H3-H4] tetrasome formation, possibly by providing preassembled histone tetramers. However, NASP does not promote disassembly of in vitro preassembled tetrasomes. In contrast to its mammalian homolog, Arabidopsis NASP is a predominantly nuclear protein. In vivo, NASP binds mainly monomeric H3.1 and H3.3. Pulldown experiments indicated that NASP may also interact with the histone chaperone MSI1 and a HSC70 heat shock protein.

Inheritance of vernalization memory at FLOWERING LOCUS C during plant regeneration

“…Enrichment was calculated relative to histone H3 for ChIP analysis. Expression analysis was done as described ( Maksimov et al , 2016 ). Gene expression values are given relative to a PP2a reference gene ( AT1G13320 ).…”

Functional Analysis of Hif1 Histone Chaperone in Saccharomyces cerevisiae

“…Similarly, Sim3 functions in the general maintenance of chromatin via its H3/H4 chaperone activities ( Tanae et al 2012 ). A recent report demonstrates an Arabidopsis NASP homolog to function as histone H3/H4-specific chaperone ( Maksimov et al 2016 ). Taken together, these studies functionally link NASP-family proteins with chromatin maintenance through dynamic histone regulation.…”

Gene modification by fast‐track recombineering for cellular localization and isolation of components of plant protein complexes

“…Among other candidates of H3.1‐interactors (Figure , Table S3), the PHD finger protein (AT4G23860) was identified as a homologue of human histone H3‐binding UBR7 E3 ubiquitin ligase, which mediates K120 ubiquitination of histone H2B and acts as breast cancer tumour suppressor (Kleiner et al ., ; Adhikary et al ., ). The tetratricopeptide repeat protein NASP (AT4G37210) was identified as a member of conserved H3‐binding SHNi‐TRP domain factors that mediate deposition of H3‐variants in yeast and Arabidopsis (Dunleavy et al ., ; Maksimov et al ., ), while the DNA‐J chaperones ATJ6 and AT3G12170 were found to be closely related to the human nuclear H3‐binding factor DNAJC9 (Campos et al ., ; Lambert et al ., ). Finally, Ku70 (AT1G16970) and Ku80 (AT1G48050) in the list of putative H3.1‐interactors represented key factors that bind to DNA ends at double‐stranded breaks and interact with components of the nonhomologous end‐joining (NHEJ) DNA repair pathway, including the human CAF1 complex (Hoek et al ., ).…”