Epigenetic modification, which involve DNA methylation, RNA-associated silencing and histone modification, is implicated in cell proliferation, differentiation, survival, apoptosis and malignant transformation. Some leukemogenesis has been shown to be aberrance of epigenetic modification. This paper discussed the potential causes of some of leukemias correlating with the methylation of cell cycle regulation genes, small interference RNA and modification abnormality of histone after translation. The study on epigenetic modification abnormality of leukemia cells provides a new strategy for treatment of leukemia.
DNA Methylation ; Epigenesis, Genetic ; Gene Silencing ; Histones ; Humans ; Leukemia ; genetics ; RNA, Small Interfering ; genetics

Epigenesis, Genetic ; Epigenomics ; Humans

Benzene ; toxicity ; Epigenesis, Genetic ; Humans

Biomarkers ; Carcinogens ; Epigenesis, Genetic ; Humans

Epigenesis, Genetic ; Humans ; Molecular Epidemiology

Despite recent successes in cloning various mammals and amphibians, the low efficiency of animals production and abnormal symptoms in many cloned animals are crucial problems in cloning technology. To overcome these problems, scientists focus on mechanisms of cloning. A possible cause of the low success frequency of cloning is the insufficient dedifferentiation and the inadequate reprogramming of the high differentiated adult somatic nucleus in enucleated oocytes, which caused by incomplete methylation and premature de novo remethylation of donor DNA. In cloned embryos the methylation level is higher than normal embryos, and this may cause aberrant expression of several important genes, especially imprinting genes. Study on these mechanisms is very important to improve the rate of successful cloned animals.
Animals ; Cloning, Organism ; DNA Methylation ; genetics ; physiology ; Epigenesis, Genetic ; genetics ; physiology ; Genomic Imprinting ; genetics ; physiology ; Humans

Epigenetics comprises the modifications made in gene expressions without changing the DNA sequence itself. Significant epigenetic changes take place during spermatogenesis and fertilization and exert direct influences on embryogenesis. This article provides an overview of the latest researches on epigenetics of male germ cells and a brief discussion on the correlation of sperm with embryogenesis in four aspects: DNA methylation, histone modification, regulation of non-coding RNAs, and genomic imprinting.
Animals ; DNA Methylation ; Embryonic Development ; Epigenesis, Genetic ; Genomic Imprinting ; Histones ; metabolism ; Humans ; Male ; Spermatozoa

Epigenetics is the study of heritable changes in gene expression other than changes in the underlying DNA sequence. Such changes include DNA methylation, histone modification, chromatin remodeling, genomic imprinting, X chromosome inactivation and non-coding RNA regulation. Recent progresses on epigenetics open new possibilities in tackling these challenging problems in forensic science, including identification of fetal paternity testing in embryonic period, determination of the necessary allele in paternity testing, discrimination of identical twins, origination analysis of micro tissue, verification of forged DNA. This review focuses on epigenetics concept and its latest application in the field of paternity testing, age estimation, discrimination between the twins, identification of tissue of origin, and estimation of postmortem interval.
Alleles ; DNA Methylation ; Epigenesis, Genetic ; Epigenomics ; Forensic Sciences ; Gene Expression ; Genomic Imprinting ; Humans ; Twins, Monozygotic

Heterochromatic siRNAs regulate transcriptional gene silencing by inducing DNA methylation and histone H3K9 dimethylation. Recent advances have revealed the distinct phases involved in siRNA mediated silencing pathway, although the precise functions of a number of factors remain undesignated, putative mechanisms for the connection between DNA and histone methylation have been investigated, and much effort has been invested to understand the biological functions of siRNA-mediated epigenetic modification. In this review, we summarize the mechanism of siRNA-mediated epigenetic modification, which involves the production of siRNA and the recruitments of DNA and histone methytransferases to the target sequences assisted by complementary pairing between 24-nt siRNAs and nascent scaffold RNAs, the roles of siRNA-mediated epigenetic modification in maintaining genome stability and regulating gene expression have been discussed, newly identified players of the siRNA mediated silencing pathway have also been introduced.
Arabidopsis ; genetics ; metabolism ; DNA Methylation ; Epigenesis, Genetic ; Gene Silencing ; Histones ; metabolism ; Methylation ; Plant Proteins ; metabolism ; Plants ; genetics ; metabolism ; RNA, Small Interfering ; biosynthesis ; genetics

Epigenetic is usually referring to heritable traits that do not involve changes to the underlying DNA sequence. DNA methylation is known to serve as cellular memory, and is one of the most important mechanism of epigenetic. DNA methylation is a covalent modification in which the target molecules for methylation in mammalian DNA are cytosine bases in CpG dinucleotides. The 5' position of cytosine is methylated in a reaction catalyzed by DNA methyltransferases; DNMT1, DNMT3a, and DNMT3b. There are two different regions in the context of DNA methylation: CpG poor regions and CpG islands. The intergenic and the intronic region is considered to be CpG poor, and CpG islands are discrete CpG-rich regions which are often found in promoter regions. Normally, CpG poor regions are usually methylated whereas CpG islands are generally hypomethylated. DNA methylation is involved in various biological processes such as tis ue-specific gene expression, genomic imprinting, and X chromosome inactivation. In general, cancer cells are characterized by global genomic hypomethylation and focal hypermethylation of CpG islands, which are generally unmethylated in normal cells. Gene silencing by CpG hypermethylation at the promotors of tumor suppressor genes is probably the most common mechanism of tumor suppressor inactivation in cancer.]]>
Base Sequence ; Biological Processes ; CpG Islands ; Cytosine ; DNA ; DNA Methylation ; Epigenomics ; Gene Expression ; Gene Silencing ; Genes, Tumor Suppressor ; Genomic Imprinting ; Introns ; Memory ; Methylation ; Promoter Regions, Genetic ; X Chromosome Inactivation