Clinical and Molecular Study of the NOG Gene in Families with Mandibular Micrognathism.

Objectives: Previous studies showed that noggin gene () sequence alterations, as well as epigenetic factors, could influence mandibular development. The aim of this study was to analyze clinical characteristics, gene sequences, and promoter methylation sites in patients with mandibular micrognathism.

Materials And Methods: A total of 35 individuals of five Colombian families were subject to clinical and cephalometric analysis for mandibular micrognathism.

time-ChIP: A Method to Determine Long-Term Locus-Specific Nucleosome Inheritance.

Understanding chromatin dynamics is essential to define the contribution of chromatin to heritable gene silencing and the long-term maintenance of gene expression. Here we present a detailed protocol for time-ChIP, a novel method to measure histone turnover at high resolution across long timescales. This method is based on the SNAP-tag, a self-labeling enzyme that can be pulse labeled with small molecules in cells.

Enhancer regions show high histone H3.3 turnover that changes during differentiation.

The organization of DNA into chromatin is dynamic; nucleosomes are frequently displaced to facilitate the ability of regulatory proteins to access specific DNA elements. To gain insight into nucleosome dynamics, and to follow how dynamics change during differentiation, we used a technique called time-ChIP to quantitatively assess histone H3.3 turnover genome-wide during differentiation of mouse ESCs.

Basic properties of epigenetic systems: lessons from the centromere.

Chromatin-based epigenetic inheritance cooperates with cis-acting DNA sequence information to propagate gene expression states and chromosome architecture across cell division cycles. Histone proteins and their modifications are central components of epigenetic systems but how, and to what extent, they are propagated is a matter of continued debate. Centromeric nucleosomes, marked by the histone H3 variant CENP-A, are stable across mitotic divisions and are assembled in a locus specific and cell cycle controlled manner.

Epigenetic engineering shows H3K4me2 is required for HJURP targeting and CENP-A assembly on a synthetic human kinetochore.

Kinetochores assemble on distinct 'centrochromatin' containing the histone H3 variant CENP-A and interspersed nucleosomes dimethylated on H3K4 (H3K4me2). Little is known about how the chromatin environment at active centromeres governs centromeric structure and function. Here, we report that centrochromatin resembles K4-K36 domains found in the body of some actively transcribed housekeeping genes.