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Multiple Sites of the Cleavage of 21- and 25-Mer Encephalytogenic Oligopeptides Corresponding to Human Myelin Basic Protein (MBP) by Specific Anti-MBP Antibodies from Patients with Systemic Lupus Erythematosus  [PDF]
Anna M. Timofeeva, Pavel S. Dmitrenok, Ludmila P. Konenkova, Valentina N. Buneva, Georgy A. Nevinsky
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0051600
Abstract: IgGs from patients with multiple sclerosis and systemic lupus erythematosus (SLE) purified on MBP-Sepharose in contrast to canonical proteases hydrolyze effectively only myelin basic protein (MBP), but not many other tested proteins. Here we have shown for the first time that anti-MBP SLE IgGs hydrolyze nonspecific tri- and tetrapeptides with an extreme low efficiency and cannot effectively hydrolyze longer 20-mer nonspecific oligopeptides corresponding to antigenic determinants (AGDs) of HIV-1 integrase. At the same time, anti-MBP SLE IgGs efficiently hydrolyze oligopeptides corresponding to AGDs of MBP. All sites of IgG-mediated proteolysis of 21-and 25-mer encephalytogenic oligopeptides corresponding to two known AGDs of MBP were found by a combination of reverse-phase chromatography, TLC, and MALDI spectrometry. Several clustered major, moderate, and minor sites of cleavage were revealed in the case of 21- and 25-mer oligopeptides. The active sites of anti-MBP abzymes are localised on their light chains, while heavy chains are responsible for the affinity of protein substrates. Interactions of intact globular proteins with both light and heavy chains of abzymes provide high affinity to MBP and specificity of this protein hydrolysis. The affinity of anti-MBP abzymes for intact MBP is approximately 1000-fold higher than for the oligopeptides. The data suggest that all oligopeptides interact mainly with the light chains of different monoclonal abzymes of total pool of IgGs, which possesses a lower affinity for substrates, and therefore, depending on the oligopeptide sequences, their hydrolysis may be less specific than globular protein and can occur in several sites.
Lupus erythematosus profundus  [cached]
Aggarwal Kamal,Jain V,Dayal Surbhi
Indian Journal of Dermatology, Venereology and Leprology , 2002,
Abstract: A case of lupus erythematosus profundus, with associated mastitis, but without any lesions of discoid lupus erythematosus or systemic lupus erythematosus is being reported.
Dynamic Distribution of Linker Histone H1.5 in Cellular Differentiation  [PDF]
Jing-Yu Li,Michaela Patterson,Hanna K. A. Mikkola,William E. Lowry,Siavash K. Kurdistani
PLOS Genetics , 2012, DOI: 10.1371/journal.pgen.1002879
Abstract: Linker histones are essential components of chromatin, but the distributions and functions of many during cellular differentiation are not well understood. Here, we show that H1.5 binds to genic and intergenic regions, forming blocks of enrichment, in differentiated human cells from all three embryonic germ layers but not in embryonic stem cells. In differentiated cells, H1.5, but not H1.3, binds preferentially to genes that encode membrane and membrane-related proteins. Strikingly, 37% of H1.5 target genes belong to gene family clusters, groups of homologous genes that are located in proximity to each other on chromosomes. H1.5 binding is associated with gene repression and is required for SIRT1 binding, H3K9me2 enrichment, and chromatin compaction. Depletion of H1.5 results in loss of SIRT1 and H3K9me2, increased chromatin accessibility, deregulation of gene expression, and decreased cell growth. Our data reveal for the first time a specific and novel function for linker histone subtype H1.5 in maintenance of condensed chromatin at defined gene families in differentiated human cells.
Reduction of Hox Gene Expression by Histone H1 Depletion  [PDF]
Yunzhe Zhang, Zheng Liu, Magdalena Medrzycki, Kaixiang Cao, Yuhong Fan
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0038829
Abstract: The evolutionarily conserved homeotic (Hox)?genes are organized in clusters and expressed collinearly to specify body patterning during embryonic development. Chromatin reorganization and decompaction are intimately connected with Hox gene activation. Linker histone H1 plays a key role in facilitating folding of higher order chromatin structure. Previous studies have shown that deletion of three somatic H1 subtypes together leads to embryonic lethality and that H1c/H1d/H1e triple knockout (TKO) embryonic stem cells (ESCs) display bulk chromatin decompaction. To investigate the potential role of H1 and higher order chromatin folding in the regulation of Hox gene expression, we systematically analyzed the expression of all 39 Hox genes in triple H1 null mouse embryos and ESCs by quantitative RT-PCR. Surprisingly, we find that H1 depletion causes significant reduction in the expression of a broad range of Hox genes in embryos and ESCs. To examine if any of the three H1 subtypes (H1c, H1d and H1e) is responsible for decreased expression of Hox gene in triple-H1 null ESCs, we derived and characterized H1c?/?, H1d?/?, and H1e?/? single-H1 null ESCs. We show that deletion of individual H1 subtypes results in down-regulation of specific Hox genes in ESCs. Finally we demonstrate that, in triple-H1- and single-H1- null ESCs, the levels of H3K4 trimethylation (H3K4me3) and H3K27 trimethylation (H3K27me3) were affected at specific Hox genes with decreased expression. Our data demonstrate that marked reduction in total H1 levels causes significant reduction in both expression and the level of active histone mark H3K4me3 at many Hox genes and that individual H1 subtypes may also contribute to the regulation of specific Hox gene expression. We suggest possible mechanisms for such an unexpected role of histone H1 in Hox gene regulation.
Histone H1 Depletion Impairs Embryonic Stem Cell Differentiation  [PDF]
Yunzhe Zhang equal contributor,Marissa Cooke equal contributor,Shiraj Panjwani equal contributor,Kaixiang Cao,Beth Krauth,Po-Yi Ho,Magdalena Medrzycki,Dawit T. Berhe,Chenyi Pan,Todd C. McDevitt,Yuhong Fan
PLOS Genetics , 2012, DOI: 10.1371/journal.pgen.1002691
Abstract: Pluripotent embryonic stem cells (ESCs) are known to possess a relatively open chromatin structure; yet, despite efforts to characterize the chromatin signatures of ESCs, the role of chromatin compaction in stem cell fate and function remains elusive. Linker histone H1 is important for higher-order chromatin folding and is essential for mammalian embryogenesis. To investigate the role of H1 and chromatin compaction in stem cell pluripotency and differentiation, we examine the differentiation of embryonic stem cells that are depleted of multiple H1 subtypes. H1c/H1d/H1e triple null ESCs are more resistant to spontaneous differentiation in adherent monolayer culture upon removal of leukemia inhibitory factor. Similarly, the majority of the triple-H1 null embryoid bodies (EBs) lack morphological structures representing the three germ layers and retain gene expression signatures characteristic of undifferentiated ESCs. Furthermore, upon neural differentiation of EBs, triple-H1 null cell cultures are deficient in neurite outgrowth and lack efficient activation of neural markers. Finally, we discover that triple-H1 null embryos and EBs fail to fully repress the expression of the pluripotency genes in comparison with wild-type controls and that H1 depletion impairs DNA methylation and changes of histone marks at promoter regions necessary for efficiently silencing pluripotency gene Oct4 during stem cell differentiation and embryogenesis. In summary, we demonstrate that H1 plays a critical role in pluripotent stem cell differentiation, and our results suggest that H1 and chromatin compaction may mediate pluripotent stem cell differentiation through epigenetic repression of the pluripotency genes.
Structural and dynamic properties of linker histone H1 binding to DNA  [PDF]
Rolf Dootz,Adriana Cristina Toma,Thomas Pfohl
Quantitative Biology , 2010,
Abstract: Found in all eukaryotic cells, linker histones H1 are known to bind to and rearrange nucleosomal linker DNA. In vitro, the fundamental nature of H1/DNA interactions has attracted wide interest among research communities - for biologists from a chromatin organization deciphering point of view, and for physicists from the study of polyelectrolyte interactions point of view. Hence, H1/DNA binding processes, structural and dynamical information about these self-assemblies is of broad importance. Targeting a quantitative understanding of H1 induced DNA compaction mechanisms our strategy is based on using small angle X-ray microdiffraction in combination with microfluidics. The usage of microfluidic hydrodynamic focusing devices facilitate a microscale control of these self-assembly processes. In addition, the method enables time-resolved access to structure formation in situ, in particular to transient intermediate states. The observed time dependent structure evolution shows that the interaction of H1 with DNA can be described as a two step process: an initial unspecific binding of H1 to DNA is followed by a rearrangement of molecules within the formed assemblies. The second step is most likely induced by interactions between the charged side chains of the protein and DNA. This leads to an increase in lattice spacing within the DNA/protein assembly and induces a decrease in the correlation length of the mesophases, probably due to a local bending of the DNA.
Interaction between linker histone H1 and non-histone chromatin protein HMGB1  [PDF]
Alexander V. Fonin,Olga V. Stepanenko,Irina M. Kuznetsova,Konstantin K. Turoverov,Elena I. Kostyleva,Vladimir I. Vorobyev
Spectroscopy: An International Journal , 2010, DOI: 10.3233/spe-2010-0417
Abstract: The possibility of interaction between linker histone H1 and non-histone chromatin protein HMGB1 was studied by intrinsic UV-fluorescence, far and near-UV CD and light scattering. The obtained data allow us to assume that the increase of histone H1 content in the HMGB1 solutions in a low ionic strength is accompanied by the destruction of HMGB1 associates. The interaction between proteins causes the increase of ordered regions in the protein molecules and the minor changes in their tertiary structure.
Bullous systemic lupus erythematosus  [cached]
Aswani V,Vaz B,Shah S,Malkani R
Indian Journal of Dermatology, Venereology and Leprology , 1993,
Abstract: Bullous systemic lupus erythematosus (BSLE) is a rare variant of systemic lupus erythematosus (SLE) which histologically resembles dermatitis herpetiformis (DH) and responds dramatically to dapsone. We report a case of bullous SLE.
组蛋白H1序列固有无序特性分析
Analysis of intrinsically disordered characteristics for histone H1
 [PDF]

王春玲,于家峰,王红梅,王吉华
- , 2016,
Abstract: 组蛋白H1对于高阶染色质结构的形成和基因表达调控具有重要作用。为了揭示组蛋白H1在染色质结构形成中的生物学机制,本文对组蛋白H1三个结构域C-terminal domain (CTD)、N-terminal domain(NTD)和Globular domain (GD) 及各区域连接位点对应序列氨基酸偏好、复杂度等序列特征进行了系统对比研究,并对各区域进行了固有序蛋白有序区/序区预测分析。结果表明,组蛋白H1三个结构中,中间的球状结构域(GD)中的氨基酸序列是非常保守的,NTD富含疏水氨基酸,CTD末端富含碱性氨基酸。进一步的研究表明, CTD和NTD两个结构域普遍具有固有序特性,因此这些区域具有较大的柔性结构,对其在染色质形成中行使的重要生物学功能具有重要意义。
Histone H1 is important both for maintenance of higher-order chromatin structure and for the regulation of gene expression. In this work, in order to reveal the biological mechanism of histone H1 in the formation of chromatin structure, the probability of amino acid, amino acid sequence complexity and the analyzes about junction of three domains are adopted to systematic comprehensive study the sequence features of the three domains(C-terminal domain (CTD), N-terminal domain(NTD) and Globular domain (GD)) of Histone H1, and the ordered / disordered protein region of each sequence is predicted. The results indicate that the amino acid sequence of the globular domain (GD) is highly conserved, NTD is rich in hydrophobic amino acids, and the CTD is rich in basic amino acids, lysine, serine, proline and alanine. Further studies show that CTD and NTD have intrinsically disorder characteristics, so the two regions have a large flexible structure, which can promote them to preform the important biological functions in the formation of the chromatin.
Fine Mapping of Posttranslational Modifications of the Linker Histone H1 from Drosophila melanogaster  [PDF]
Ana Villar-Garea, Axel Imhof
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001553
Abstract: The linker histone H1 binds to the DNA in between adjacent nucleosomes and contributes to chromatin organization and transcriptional control. It is known that H1 carries diverse posttranslational modifications (PTMs), including phosphorylation, lysine methylation and ADP-ribosylation. Their biological functions, however, remain largely unclear. This is in part due to the fact that most of the studies have been performed in organisms that have several H1 variants, which complicates the analyses. We have chosen Drosophila melanogaster, a model organism, which has a single H1 variant, to approach the study of the role of H1 PTMs during embryonic development. Mass spectrometry mapping of the entire sequence of the protein showed phosphorylation only in the ten N-terminal amino acids, mostly at S10. For the first time, changes in the PTMs of a linker H1 during the development of a multicellular organism are reported. The abundance of H1 monophosphorylated at S10 decreases as the embryos age, which suggests that this PTM is related to cell cycle progression and/or cell differentiation. Additionally, we have found a polymorphism in the protein sequence that can be mistaken with lysine methylation if the analysis is not rigorous.
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