Epigenetic modifications, such as acetylation, phosphorylation, methylation, ubiquitination, and ADP ribosylation, of the highly conserved core histones, H2A, H2B, H3, and H4, influence the genetic potential of DNA. The enormous regulatory potential of histone modification is illustrated in the vast array of epigenetic markers found throughout the genome. More than the other types of histone modification, acetylation and methylation of specific lysine residues on N-terminal histone tails are fundamental for the formation of chromatin domains, such as euchromatin, and facultative and constitutive heterochromatin. In addition, the modification of histones can cause a region of chromatin to undergo nuclear compartmentalization and, as such, specific epigenetic markers are non-randomly distributed within interphase nuclei. In this review, we summarize the principles behind epigenetic compartmentalization and the functional consequences of chromatin arrangement within interphase nuclei.

• MeSH
• acetylace MeSH
• buněčné jádro metabolismus   ultrastruktura   MeSH
• chromatin ultrastruktura   MeSH
• chromozomální proteiny, nehistonové fyziologie   MeSH
• epigeneze genetická MeSH
• exprese genu MeSH
• financování organizované MeSH
• histony genetika   metabolismus   MeSH
• interfáze MeSH
• lidé MeSH
• lidské chromozomy X metabolismus   MeSH
• metylace MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• přehledy MeSH

BACKGROUND: ChIP-seq has become a routine method for interrogating the genome-wide distribution of various histone modifications. An important experimental goal is to compare the ChIP-seq profiles between an experimental sample and a reference sample, and to identify regions that show differential enrichment. However, comparative analysis of samples remains challenging for histone modifications with broad domains, such as heterochromatin-associated H3K27me3, as most ChIP-seq algorithms are designed to detect well defined peak-like features. RESULTS: To address this limitation we introduce histoneHMM, a powerful bivariate Hidden Markov Model for the differential analysis of histone modifications with broad genomic footprints. histoneHMM aggregates short-reads over larger regions and takes the resulting bivariate read counts as inputs for an unsupervised classification procedure, requiring no further tuning parameters. histoneHMM outputs probabilistic classifications of genomic regions as being either modified in both samples, unmodified in both samples or differentially modified between samples. We extensively tested histoneHMM in the context of two broad repressive marks, H3K27me3 and H3K9me3, and evaluated region calls with follow up qPCR as well as RNA-seq data. Our results show that histoneHMM outperforms competing methods in detecting functionally relevant differentially modified regions. CONCLUSION: histoneHMM is a fast algorithm written in C++ and compiled as an R package. It runs in the popular R computing environment and thus seamlessly integrates with the extensive bioinformatic tool sets available through Bioconductor. This makeshistoneHMM an attractive choice for the differential analysis of ChIP-seq data. Software is available from http://histonehmm.molgen.mpg.de .

• MeSH
• algoritmy * MeSH
• chromatinová imunoprecipitace MeSH
• genomika metody   MeSH
• histony chemie   genetika   metabolismus   MeSH
• krysa rodu rattus MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• lidé MeSH
• Markovovy řetězce MeSH
• myši MeSH
• posttranslační úpravy proteinů * MeSH
• software * MeSH
• výpočetní biologie metody   MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A high degree of developmental plasticity enables plants to adapt to continuous, often unfavorable and unpredictable changes in their environment. At the molecular level, adaptive advantages for plants are primarily provided by epigenetic machinery including DNA methylation, histone modifications, and the activity of noncoding RNA molecules. Using a mass spectrometry-based proteomic approach, we examined the levels of acetylated histone peptide forms in Arabidopsis plants with a loss of function of histone deacetylase 6 (HDA6), and in plants germinated in the presence of HDA inhibitors trichostatin A (TSA) and sodium butyrate (NaB). Our analyses revealed particular lysine sites at histone sequences targeted by the HDA6 enzyme, and by TSA- and NaB-sensitive HDAs. Compared with plants exposed to drugs, more dramatic changes in the overall profiles of histone post-translational modifications were identified in hda6 mutants. However, loss of HDA6 was not sufficient by itself to induce hyperacetylation to the maximum degree, implying complementary activities of other HDAs. In contrast to hda6 mutants that did not exhibit any obvious phenotypic defects, the phenotypes of seedlings exposed to HDA inhibitors were markedly affected, showing that the effect of these drugs on early plant development is not limited to the modulation of histone acetylation levels.

• MeSH
• Arabidopsis genetika   růst a vývoj   MeSH
• histondeacetylasy genetika   MeSH
• histonový kód účinky léků   genetika   MeSH
• inhibitory histondeacetylas farmakologie   MeSH
• klíčení genetika   MeSH
• kyselina máselná farmakologie   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• metylace DNA účinky léků   MeSH
• proteiny huseníčku antagonisté a inhibitory   genetika   MeSH
• proteomika * MeSH
• regulace genové exprese u rostlin MeSH
• semenáček účinky léků   genetika   MeSH
• umlčování genů MeSH
• vývoj rostlin účinky léků   genetika   MeSH
• Publikační typ
• časopisecké články MeSH

We examined the levels and distribution of post-translationally modified histones and protamines in human sperm. Using western blot immunoassay, immunofluorescence, mass spectrometry (MS), and FLIM-FRET approaches, we analyzed the status of histone modifications and the protamine P2. Among individual samples, we observed variability in the levels of H3K9me1, H3K9me2, H3K27me3, H3K36me3, and H3K79me1, but the level of acetylated (ac) histones H4 was relatively stable in the sperm head fractions, as demonstrated by western blot analysis. Sperm heads with lower levels of P2 exhibited lower levels of H3K9ac, H3K9me1, H3K27me3, H3K36me3, and H3K79me1. A very strong correlation was observed between the levels of P2 and H3K9me2. FLIM-FRET analysis additionally revealed that acetylated histones H4 are not only parts of sperm chromatin but also appear in a non-integrated form. Intriguingly, H4ac and H3K27me3 were detected in sperm tail fractions via western blot analysis. An appearance of specific histone H3 and H4 acetylation and H3 methylation in sperm tail fractions was also confirmed by both LC-MS/MS and MALDI-TOF MS analysis. Taken together, these data indicate that particular post-translational modifications of histones are uniquely distributed in human sperm, and this distribution varies among individuals and among the sperm of a single individual.

• MeSH
• acetylace MeSH
• chromatin genetika   MeSH
• histonlysin-N-methyltransferasa biosyntéza   genetika   MeSH
• histony genetika   metabolismus   MeSH
• lidé MeSH
• metylace MeSH
• posttranslační úpravy proteinů genetika   MeSH
• sekvence aminokyselin MeSH
• spermie růst a vývoj   metabolismus   MeSH
• tandemová hmotnostní spektrometrie MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• antioxidancia MeSH
• chromatin MeSH
• genetická transkripce * MeSH
• heterochromatin MeSH
• histondeacetylasy * MeSH
• histony MeSH
• kalorická restrikce MeSH
• lidé MeSH
• NAD+ nukleosidasa MeSH
• posttranslační úpravy proteinů * MeSH
• sirtuiny * fyziologie   klasifikace   metabolismus   MeSH
• stárnutí MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

Aging is the most critical factor that influences the quality of post-ovulatory oocytes. Age-related molecular pathways remain poorly understood in fish oocytes. In this study, we examined the effect of oocyte aging on specific histone acetylation in common carp Cyprinus carpio. The capacity to progress to the larval stage in oocytes that were aged for 28 h in vivo and in vitro was evaluated. Global histone modifications and specific histone acetylation (H3K9ac, H3K14ac, H4K5ac, H4K8ac, H4K12ac, and H4K16ac) were investigated during oocyte aging. Furthermore, the activity of histone acetyltransferase (HAT) was assessed in fresh and aged oocytes. Global histone modifications did not exhibit significant alterations during 8 h of oocyte aging. Among the selected modifications, H4K12ac increased significantly at 28 h post-stripping (HPS). Although not significantly different, HAT activity exhibited an upward trend during oocyte aging. Results of our current study indicate that aging of common carp oocytes for 12 h results in complete loss of egg viability rates without any consequence in global and specific histone modifications. However, aging oocytes for 28 h led to increased H4K12ac. Thus, histone acetylation modification as a crucial epigenetic mediator may be associated with age-related defects, particularly in oocytes of a more advanced age.

• MeSH
• acetylace MeSH
• histonacetyltransferasy genetika   MeSH
• histony genetika   MeSH
• kapři genetika   růst a vývoj   MeSH
• oocyty růst a vývoj   metabolismus   MeSH
• posttranslační úpravy proteinů genetika   MeSH
• stárnutí genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Histone modifications are epigenetic marks that play fundamental roles in many biological processes including the control of chromatin-mediated regulation of gene expression. Little is known about interindividual variability of histone modification levels across the genome and to what extent they are influenced by genetic variation. We annotated the rat genome with histone modification maps, identified differences in histone trimethyl-lysine levels among strains, and described their underlying genetic basis at the genome-wide scale using ChIP-seq in heart and liver tissues in a panel of rat recombinant inbred and their progenitor strains. We identified extensive variation of histone methylation levels among individuals and mapped hundreds of underlying cis- and trans-acting loci throughout the genome that regulate histone methylation levels in an allele-specific manner. Interestingly, most histone methylation level variation was trans-linked and the most prominent QTL identified influenced H3K4me3 levels at 899 putative promoters throughout the genome in the heart. Cis- acting variation was enriched in binding sites of distinct transcription factors in heart and liver. The integrated analysis of DNA variation together with histone methylation and gene expression levels showed that histoneQTLs are an important predictor of gene expression and that a joint analysis significantly enhanced the prediction of gene expression traits (eQTLs). Our data suggest that genetic variation has a widespread impact on histone trimethylation marks that may help to uncover novel genotype-phenotype relationships.

• MeSH
• epigeneze genetická * MeSH
• genetická transkripce MeSH
• genetická variace * MeSH
• genom * MeSH
• histony genetika   metabolismus   MeSH
• inbrední kmeny potkanů MeSH
• játra metabolismus   MeSH
• krysa rodu rattus MeSH
• lokus kvantitativního znaku MeSH
• metylace MeSH
• myokard metabolismus   MeSH
• posttranslační úpravy proteinů * MeSH
• promotorové oblasti (genetika) MeSH
• transkripční faktory genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Trypsin dominates bottom-up proteomics, but there are reasons to consider alternative enzymes. Improving sequence coverage, exposing proteomic "dark matter," and clustering post-translational modifications in different ways and with higher-order drive the pursuit of reagents complementary to trypsin. Additionally, enzymes that are easy to use and generate larger peptides that capitalize upon newer fragmentation technologies should have a place in proteomics. We expressed and characterized recombinant neprosin, a novel prolyl endoprotease of the DUF239 family, which preferentially cleaves C-terminal to proline residues under highly acidic conditions. Cleavage also occurs C-terminal to alanine with some frequency, but with an intriguingly high "skipping rate." Digestion proceeds to a stable end point, resulting in an average peptide mass of 2521 units and a higher dependence upon electron-transfer dissociation for peptide-spectrum matches. In contrast to most proline-cleaving enzymes, neprosin effectively degrades proteins of any size. For 1251 HeLa cell proteins identified in common using trypsin, Lys-C, and neprosin, almost 50% of the neprosin sequence contribution is unique. The high average peptide mass coupled with cleavage at residues not usually modified provide new opportunities for profiling clusters of post-translational modifications. We show that neprosin is a useful reagent for reading epigenetic marks on histones. It generates peptide 1-38 of histone H3 and peptide 1-32 of histone H4 in a single digest, permitting the analysis of co-occurring post-translational modifications in these important N-terminal tails.

• MeSH
• HeLa buňky MeSH
• histony chemie   metabolismus   MeSH
• lidé MeSH
• peptidy metabolismus   MeSH
• posttranslační úpravy proteinů MeSH
• proteasy metabolismus   MeSH
• proteomika metody   MeSH
• rekombinantní proteiny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

MAIN CONCLUSION: Contrasting patterns of histone modifications between the X and Y chromosome in Silene latifolia show euchromatic histone mark depletion on the Y chromosome and indicate hyperactivation of one X chromosome in females. Silene latifolia (white campion) is a dioecious plant with heteromorphic sex chromosomes (24, XX in females and 24, XY in males), and a genetically degenerated Y chromosome that is 1.4 times larger than the X chromosome. Although the two sex chromosomes differ in their DNA content, information about epigenetic histone marks and evidence of their function are scarce. We performed immunolabeling experiments using antibodies specific for active and suppressive histone modifications as well as pericentromere-specific histone modifications. We show that the Y chromosome is partially depleted of histone modifications important for transcriptionally active chromatin, and carries these marks only in the pseudo-autosomal region, but that it is not enriched for suppressive and pericentromere histone marks. We also show that two of the active marks are specifically enriched in one of the X chromosomes in females and in the X chromosome in males. Our data support recent findings that genetic imprinting mediates dosage compensation of sex chromosomes in S. latifolia.

• MeSH
• chromozomy rostlin genetika   MeSH
• epigeneze genetická * MeSH
• histonový kód genetika   MeSH
• Silene genetika   MeSH
• Publikační typ
• časopisecké články MeSH

The effects of the histone deacetylase inhibitors (HDACi) trichostatin A (TSA) and sodium butyrate (NaBt) were studied in A549, HT29 and FHC human cell lines. Global histone hyperacetylation, leading to decondensation of interphase chromatin, was characterized by an increase in H3(K9) and H3(K4) dimethylation and H3(K9) acetylation. The levels of all isoforms of heterochromatin protein, HP1, were reduced after HDAC inhibition. The observed changes in the protein levels were accompanied by changes in their interphase patterns. In control cells, H3(K9) acetylation and H3(K4) dimethylation were substantially reduced to a thin layer at the nuclear periphery, whereas TSA and NaBt caused the peripheral regions to become intensely acetylated at H3(K9) and dimethylated at H3(K4). The dispersed pattern of H3(K9) dimethylation was stable even at the nuclear periphery of HDACi-treated cells. After TSA and NaBt treatment, the HP1 proteins were repositioned more internally in the nucleus, being closely associated with interchromatin compartments, while centromeric heterochromatin was relocated closer to the nuclear periphery. These findings strongly suggest dissociation of HP1 proteins from peripherally located centromeres in a hyperacetylated and H3(K4) dimethylated environment. We conclude that inhibition of histone deacetylases caused dynamic reorganization of chromatin in parallel with changes in its epigenetic modifications.

• MeSH
• apoptóza účinky záření   MeSH
• buněčné jádro enzymologie   genetika   metabolismus   účinky léků   MeSH
• buněčné linie MeSH
• buněčný cyklus účinky léků   MeSH
• buňky HT-29 MeSH
• chromatin metabolismus   MeSH
• chromozomální proteiny, nehistonové antagonisté a inhibitory   metabolismus   MeSH
• financování organizované MeSH
• histondeacetylasy metabolismus   MeSH
• histony metabolismus   MeSH
• inhibitory enzymů farmakologie   MeSH
• inhibitory histondeacetylas MeSH
• interfáze účinky léků   MeSH
• kyselina máselná farmakologie   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• malobuněčný karcinom enzymologie   metabolismus   patologie   MeSH
• nádorové buněčné linie MeSH
• nádory plic enzymologie   metabolismus   patologie   MeSH
• nádory tračníku enzymologie   metabolismus   patologie   MeSH
• plod MeSH
• Check Tag
• lidé MeSH