scholarly journals Label-Free Mass Spectrometry-Based Quantification of Linker Histone H1 Variants in Clinical Samples

2020 ◽  
Vol 21 (19) ◽  
pp. 7330
Author(s):  
Roberta Noberini ◽  
Cristina Morales Torres ◽  
Evelyn Oliva Savoia ◽  
Stefania Brandini ◽  
Maria Giovanna Jodice ◽  
...  

Epigenetic aberrations have been recognized as important contributors to cancer onset and development, and increasing evidence suggests that linker histone H1 variants may serve as biomarkers useful for patient stratification, as well as play an important role as drivers in cancer. Although traditionally histone H1 levels have been studied using antibody-based methods and RNA expression, these approaches suffer from limitations. Mass spectrometry (MS)-based proteomics represents the ideal tool to accurately quantify relative changes in protein abundance within complex samples. In this study, we used a label-free quantification approach to simultaneously analyze all somatic histone H1 variants in clinical samples and verified its applicability to laser micro-dissected tissue areas containing as low as 1000 cells. We then applied it to breast cancer patient samples, identifying differences in linker histone variants patters in primary triple-negative breast tumors with and without relapse after chemotherapy. This study highlights how label-free quantitation by MS is a valuable option to accurately quantitate histone H1 levels in different types of clinical samples, including very low-abundance patient tissues.

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Michelle S Parvatiyar ◽  
Timothy D Lopez ◽  
Sarah Franklin ◽  
Thomas M Vondriska

Heart failure results when cardiac output is insufficient to meet physiological requirements and is often preceded by development of cardiomyocyte hypertrophy. As cardiac myocytes respond to hypertrophic stresses they re-express developmentally important genes, normally senescent in the adult. The chromatin structural events underlying this “fetal gene program” are unknown. We previously showed by proteomics that histones, components of the chromatin protein functional unit, the nucleosome, are altered during hypertrophic and failing phases of pressure overload in mouse: linker histone variants H1.2 and H1.5 decreased in hypertrophied myocardium while H1.0 increased during the transition to failure. The linker histone H1 family influences higher order chromatin structure and gene expression, although the role of this family in the heart is unknown. To assess the role of linker histones in hypertrophy, neonatal rat ventricular cardiomyocytes (NRVMs) were transfected with siRNAs individually targeting six H1 variants. Loss of H1.3 and H1.4 respectively induced a significant 26.1% (76 of 90) and 13.5% (80 of 94) increase in cell size area (µm2). A role of H1 in the hypertrophic response is evidenced by its influence on myosin heavy chain (MHC) mRNA expression. Knock-down of individual H1 variants significantly altered the MHC isoform ratio: loss of H1.3 increased α-MHC levels 1.5 fold and decreased β-MHC 1.6 fold while H1.5 depletion decreased α-MHC 2.5 fold. Both H1.3 and H1.4 knock-down increased atrial natriuretic factor (ANF) 1.3 fold while H1.5 loss decreased ANF 6.2 fold shown by qRT-PCR. Treatment with hypertrophy-inducing agents Isoproterenol (1μM), Endothelin (2nM) or Phenylephrine (10μM), reduced H1 mRNA levels however with subtle effects on protein abundance. To evaluate whether H1 loss shifted NRVM nuclei from a predominantly heterochromatic toward euchromatic state favoring gene accessibility we examined distinct histone markers of chromatin states. Histone H1.5 knock-down significantly decreased H3K9Me3 levels, a silencing mark associated with heterochromatin, 1.7 fold. Therefore we conclude that variants package distinctive regions of the genome and that H1.3 and H1.4 controls genes involved in the hypertrophic response.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Eva Höllmüller ◽  
Simon Geigges ◽  
Marie L. Niedermeier ◽  
Kai-Michael Kammer ◽  
Simon M. Kienle ◽  
...  

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.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pierre Bourguet ◽  
Colette L. Picard ◽  
Ramesh Yelagandula ◽  
Thierry Pélissier ◽  
Zdravko J. Lorković ◽  
...  

AbstractIn flowering plants, heterochromatin is demarcated by the histone variant H2A.W, elevated levels of the linker histone H1, and specific epigenetic modifications, such as high levels of DNA methylation at both CG and non-CG sites. How H2A.W regulates heterochromatin organization and interacts with other heterochromatic features is unclear. Here, we create a h2a.w null mutant via CRISPR-Cas9, h2a.w-2, to analyze the in vivo function of H2A.W. We find that H2A.W antagonizes deposition of H1 at heterochromatin and that non-CG methylation and accessibility are moderately decreased in h2a.w-2 heterochromatin. Compared to H1 loss alone, combined loss of H1 and H2A.W greatly increases accessibility and facilitates non-CG DNA methylation in heterochromatin, suggesting co-regulation of heterochromatic features by H2A.W and H1. Our results suggest that H2A.W helps maintain optimal heterochromatin accessibility and DNA methylation by promoting chromatin compaction together with H1, while also inhibiting excessive H1 incorporation.


2007 ◽  
Vol 53 (4) ◽  
pp. 199-205 ◽  
Author(s):  
Piotr Jedrzejczak ◽  
Bartosz Kempisty ◽  
Artur Bryja ◽  
M. Mostowska ◽  
Magdalena Depa-Martynow ◽  
...  

2002 ◽  
Vol 158 (7) ◽  
pp. 1161-1170 ◽  
Author(s):  
Yali Dou ◽  
Josephine Bowen ◽  
Yifan Liu ◽  
Martin A. Gorovsky

In Tetrahymena cells, phosphorylation of linker histone H1 regulates transcription of specific genes. Phosphorylation acts by creating a localized negative charge patch and phenocopies the loss of H1 from chromatin, suggesting that it affects transcription by regulating the dissociation of H1 from chromatin. To test this hypothesis, we used FRAP of GFP-tagged H1 to analyze the effects of mutations that either eliminate or mimic phosphorylation on the binding of H1 to chromatin both in vivo and in vitro. We demonstrate that phosphorylation can increase the rate of dissociation of H1 from chromatin, providing a mechanism by which it can affect H1 function in vivo. We also demonstrate a previously undescribed ATP-dependent process that has a global effect on the dynamic binding of linker histone to chromatin.


2021 ◽  
Vol 22 (22) ◽  
pp. 12127
Author(s):  
Natalya V. Maluchenko ◽  
Dmitry K. Nilov ◽  
Sergey V. Pushkarev ◽  
Elena Y. Kotova ◽  
Nadezhda S. Gerasimova ◽  
...  

Poly(ADP-ribose) polymerase 1 (PARP1) is an enzyme involved in DNA repair, chromatin organization and transcription. During transcription initiation, PARP1 interacts with gene promoters where it binds to nucleosomes, replaces linker histone H1 and participates in gene regulation. However, the mechanisms of PARP1-nucleosome interaction remain unknown. Here, using spFRET microscopy, molecular dynamics and biochemical approaches we identified several different PARP1-nucleosome complexes and two types of PARP1 binding to mononucleosomes: at DNA ends and end-independent. Two or three molecules of PARP1 can bind to a nucleosome depending on the presence of linker DNA and can induce reorganization of the entire nucleosome that is independent of catalytic activity of PARP1. Nucleosome reorganization depends upon binding of PARP1 to nucleosomal DNA, likely near the binding site of linker histone H1. The data suggest that PARP1 can induce the formation of an alternative nucleosome state that is likely involved in gene regulation and DNA repair.


2019 ◽  
Vol 2 (1) ◽  
pp. 8 ◽  
Author(s):  
Jesse Meyer

The identification of nearly all proteins in a biological system using data-dependent acquisition (DDA) tandem mass spectrometry has become routine for organisms with relatively small genomes such as bacteria and yeast. Still, the quantification of the identified proteins may be a complex process and often requires multiple different software packages. In this protocol, I describe a flexible strategy for the identification and label-free quantification of proteins from bottom-up proteomics experiments. This method can be used to quantify all the detectable proteins in any DDA dataset collected with high-resolution precursor scans and may be used to quantify proteome remodeling in response to drug treatment or a gene knockout. Notably, the method is statistically rigorous, uses the latest and fastest freely-available software, and the entire protocol can be completed in a few hours with a small number of data files from the analysis of yeast.


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