Analysis of DNA Methylation Patterns in Single Blastocysts by Pyrosequencing®.

Extensive epigenetic reprogramming occurs during mammalian gametogenesis and preimplantation development. DNA methylation patterns that are laid down during these stages are essential for subsequent normal foetal development. The requirement for more precise assessment of the epigenetic programming of in vitro-derived human preimplantation embryo has become of paramount importance following the identification of epigenetic diseases that are associated with assisted reproduction and/or infertility.

Predictors of insulin resistance in pediatric burn injury survivors 24 to 36 months postburn.

Burn injury is a dramatic event with acute and chronic consequences including insulin resistance. However, factors associated with insulin resistance have not been previously investigated. The purpose of this study was to identify factors associated with long-term insulin resistance in pediatric burn injury survivors.

Imprinted chromatin around DIRAS3 regulates alternative splicing of GNG12-AS1, a long noncoding RNA.

Imprinted gene clusters are regulated by long noncoding RNAs (lncRNAs), CCCTC binding factor (CTCF)-mediated boundaries, and DNA methylation. DIRAS3 (also known as ARH1 or NOEY1) is an imprinted gene encoding a protein belonging to the RAS superfamily of GTPases and is located within an intron of a lncRNA called GNG12-AS1. In this study, we investigated whether GNG12-AS1 is imprinted and coregulated with DIRAS3.

Quantitative analysis of DNA methylation of imprinted genes in single human blastocysts by pyrosequencing.

We report the first quantitative assessment of DNA methylation for any gene in the human preimplantation embryo to reveal that imprints exist at KvDMR1, RB1, SNRPN, and GRB10 in the human blastocyst. For comparison, in two human embryonic stem cell lines, imprints were also observed at KvDMR1, SNRPN, GRB10, and other imprinted loci, whereas RB1 and MEG3 were hypermethylated.

Quantitative analysis of DNA methylation at all human imprinted regions reveals preservation of epigenetic stability in adult somatic tissue.

Background: Genes subject to genomic imprinting are mono-allelically expressed in a parent-of-origin dependent manner. Each imprinted locus has at least one differentially methylated region (DMR) which has allele specific DNA methylation and contributes to imprinted gene expression. Once DMRs are established, they are potentially able to withstand normal genome reprogramming events that occur during cell differentiation and germ-line DMRs are stably maintained throughout development.

Cohesin is required for higher-order chromatin conformation at the imprinted IGF2-H19 locus.

Cohesin is a chromatin-associated protein complex that mediates sister chromatid cohesion by connecting replicated DNA molecules. Cohesin also has important roles in gene regulation, but the mechanistic basis of this function is poorly understood. In mammalian genomes, cohesin co-localizes with CCCTC binding factor (CTCF), a zinc finger protein implicated in multiple gene regulatory events.