Chromosomal Proteins, Non-Histone ; chemistry ; genetics ; metabolism ; HeLa Cells ; Histones ; chemistry ; genetics ; metabolism ; Humans ; Protein Domains

Cell Cycle Proteins ; chemistry ; Histones ; chemistry ; Humans ; Minichromosome Maintenance Complex Component 2 ; chemistry ; Models, Molecular ; Protein Multimerization ; Protein Structure, Quaternary

Mixed linked leukemia 4 (MLL4) is a specific methyltransferase of histone 3 position lysine 4 (H3K4). It is also one of the important members of COMPASS/Set1-like protein complex. Both MLL4 protein itself and its mediated H3K4 methylation modification can cause changes in chromatin structure and function, thus regulating gene transcription and expression. With the studies of MLL4 protein in recent years, the roles of MLL4 gene, MLL4 protein and protein complex in the development of tissues and organs, tumor diseases and other physiological and pathophysiological processes have been gradually revealed. In this paper, the research progress of MLL4 gene, MLL4 protein characteristics, biological function and its effect on disease were reviewed, in order to further understand the effect of histone methyltransferase on gene expression regulation, as well as its non-enzyme dependent function. This paper may provide new ideas for the prevention, diagnosis and treatment of related diseases.
DNA-Binding Proteins ; physiology ; Histone-Lysine N-Methyltransferase ; physiology ; Histones ; chemistry ; Humans ; Methylation

This study investigated the inhibitory effects of curcumin on proliferation of hematological malignant cells in vitro and the anti-tumor mechanism at histone acetylation/histone deacetylation levels. The effects of curcumin and histone deacetylase inhibitor trichostatin A (TSA) on the growth of Raji cells were tested by MTT assay. The expression of acetylated histone-3 (H(3)) in Raji, HL60 and K562 cells, and peripheral blood mononuclear cells (PBMCs) treated with curcumin or TSA was detected by immunohistochemistry and FACS. The results showed curcumin inhibited proliferation of Raji cells significantly in a time- and dose-dependent fashion, while exhibited low toxicity in PBMCs. Curcumin induced up-regulation of the expression of acetylated H(3) dose-dependently in all malignant cell lines tested. In conclusion, curcumin inhibited proliferation of Raji cells selectively, enhanced the level of acetylated (H(3)) in Raji, HL60, and K562 cells, which acted as a histone deacetylase inhibitor like TSA. Furthermore, up-regulation of H(3) acetylation may play an important role in regulating the proliferation of Raji cells.
Acetylation/drug effects ; Antineoplastic Agents/*pharmacology ; Cell Proliferation/*drug effects ; Curcumin/*pharmacology ; HL-60 Cells ; Histone Deacetylase Inhibitors/pharmacology ; Histones/chemistry ; Histones/*drug effects ; K562 Cells ; Triclosan/pharmacology

Binding Sites ; Histone-Lysine N-Methyltransferase ; chemistry ; metabolism ; Histones ; chemistry ; metabolism ; Humans ; Methylation ; Multiprotein Complexes ; chemistry ; metabolism ; Nuclear Proteins ; chemistry ; metabolism ; Protein Binding ; Protein Conformation ; Yeasts ; chemistry

Therapeutic monoclonal antibodies become the major product class within the biopharmaceutical market. Protein A as the first capture step is still dominant in current platforms for purification of monoclonal antibodies. In this study, we developed a new antibody harvest process that incorporates acidic treatment of cell harvest, demonstrating high process yield, improved clearance of host cell associated contaminants, like non-histone host cell protein, histone, DNA and heteroaggregates. Host protein contamination was reduced about 10-fold compared to protein A loaded with harvest clarified by centrifugation and microfiltration. Turbidity increase of eluted IgG upon pH neutralization was nearly eliminated. Residual levels of impurities in the protein A eluate were achieved that potentially meet requirements of drug substance and thus alleviate the burden for further impurities removal in subsequent chromatography steps. The mechanism of host cell associated contaminants removal during acidic treatment was also explored. After a polishing step by Capto adhere, host cell protein was reduced to less than 5 ppm, DNA less than 1 ppb, histone to undetectable level, heteroaggregates less than 0.01% with total IgG recovery around 87%. This efficient process can be easily integrated into current IgG purification platforms, and may overcome downstream processing challenges.
Antibodies, Monoclonal ; isolation & purification ; Biotechnology ; Chromatography, Affinity ; DNA ; Histones ; Hydrogen-Ion Concentration ; Immunoglobulin G ; isolation & purification ; Staphylococcal Protein A ; chemistry

Histone modification is an important mechanism in oncogenesis and development of hematologic malignancies. Acetylation of lysine residues on histones and opening chromatin are correlated with activation of genes, whereas lysine residues methylation can result in either activation or repression on expressions of chromatin. The main point of all is deacetylation of histone mediated by histone deacetylases (HDACs). HDAC inhibitors are divided into 4 categories: short-chain fatty acids, hydroxamic acids, cyclic tetrapeptides and benzamides, owning different mechanisms in HDAC inhibition. Many kinds of I/II phase clinical tests showed that all these HDAC inhibitors have obviously therapeutic efficacies in treatment of hematologic malignancies with low poisons. Combination of HDAC inhibitors with DNA demethylation drugs can decrease DNA methylation, increase histone acetylation and recover antioncogene expression. As important parts of epigenetics, histone acetylation and HDAC inhibitors possess positive prospects in treatment of hematologic malignancies. In this review the advances of study on mechanisms of histone modification, HDAC inhibitors and their use in treatment of hematologic malignancies are summarized.
Acetylation ; Hematologic Neoplasms ; drug therapy ; Histone Deacetylase Inhibitors ; therapeutic use ; Histone Deacetylases ; genetics ; Histones ; chemistry ; genetics ; metabolism

In eukaryotic cells, histones are packaged into octameric core particles with DNA wrapping around to form nucleosomes, which are the basic units of chromatin (Kornberg and Thomas, 1974). Multicellular organisms utilise chromatin marks to translate one single genome into hundreds of epigenomes for their corresponding cell types. Inheritance of epigenetic status is critical for the maintenance of gene expression profile during mitotic cell divisions (Allis et al., 2006). During S phase, canonical histones are deposited onto DNA in a replication-coupled manner (Allis et al., 2006). To understand how dividing cells overcome the dilution of epigenetic marks after chromatin duplication, DNA replication coupled (RC) nucleosome assembly has been of great interest. In this review, we focus on the potential influence of RC nucleosome assembly processes on the maintenance of epigenetic status.
Animals ; Chromatin Assembly and Disassembly ; genetics ; physiology ; DNA Replication ; Epigenesis, Genetic ; Histones ; chemistry ; physiology ; Humans ; Nucleosomes ; genetics ; physiology ; Protein Structure, Quaternary

Histone deacetylase (HDAC) has been highlighted as one of key players in tumorigenesis and angiogenesis. Recently, several derivatives of psammaplin (Psams) from a marine sponge have been known to inhibit the HDAC activity, but the molecular mechanism for the inhibition has not fully understood. Here, we explored the mode of action of Psams for the inhibition of HDAC activity in the molecular and cellular level. Among the derivatives, psammaplin A (Psam A) showed the potent inhibitory activity in enzyme assay and anti-proliferation assay with IC50 value of 0.003 and 1 microM, respectively. Psam A selectively induced hyperacetylation of histones in the cells, resulting in the upregulation of gelsolin, a well-known HDAC target gene, in a transcriptional level. In addition, reduced Psam A showed a stronger inhibitory activity than that of non-reduced one. Notably, glutathione-depleted cells were not sensitive to Psam A, implying that cellular reduction of the compound is responsible for the HDAC inhibition of Psam A after uptake into the cells. Together, these data demonstrate that Psam A could exhibit its activity under the reduced condition in the cells and be a new natural prodrug targeting HDAC.
Tyrosine/*analogs & derivatives/chemistry/pharmacology ; Prodrugs/chemistry/*pharmacology ; Oxidation-Reduction ; Molecular Structure ; Humans ; Histones/metabolism ; Histone Deacetylases/*antagonists & inhibitors/*classification/genetics/metabolism ; Hela Cells ; Enzyme Inhibitors/chemistry/*pharmacology ; Disulfides/chemistry/*pharmacology ; Cell Proliferation ; Biological Products/chemistry/*pharmacology ; Acetylation

OBJECTIVETo develop a real-time PCR-based chromatin immunoprecipitation (ChIP) assay for determining the effect of sodium butyrate on acetylation of histone in gamma-globin gene promoter regions in K562 cells.

METHODSK562 cells were grown in the presence or absence of 0.5 mmol/L sodium butyrate for 48 h, and 1=10(7) cells per group were used for real-time PCR-based ChIP with anti-acetylated histone H3 or H4 antibodies. The levels of acetylated histone H3 and H4 (acH3 and acH4) in Ggamma- and Agamma-globin gene promoter regions were measured.

RESULTSIn the K562 cells with sodium butyrate treatment or without any treatment, the levels of acH3 or acH4 in Ggamma- or Agamma-globin gene promoter were higher than that in the necdin gene (negative control). Compared with the untreated K562 cells, the cells treated with 0.5 mmol/L sodium butyrate showed a 3.1-fold or 2.6-fold increase in acH3 or acH4 in Ggamma-globin gene promoter region, with also a 3.7-fold or 3.2-fold increase in acH3 or acH4 in Agamma-globin gene promoter region, respectively (P<0.01).

CONCLUSIONWe have successfully developed a real-time PCR-based ChIP assay for analyzing the acetylation of histone H3 and H4 in gamma-globin gene promoter regions. Our results support the role of sodium butyrate in increasing the level of acetylated histone in gamma-globin gene promoter regions.

Acetylation ; Butyrates ; pharmacology ; Chromatin Immunoprecipitation ; methods ; Histones ; chemistry ; Humans ; K562 Cells ; Promoter Regions, Genetic ; genetics ; Real-Time Polymerase Chain Reaction ; methods ; gamma-Globins ; genetics