ABSTRACT
Proper regulation and maintenance of the epigenome is necessary to preserve genome function. However, in every cell division, the epigenetic state is disassembled and then reassembled in the wake of the DNA replication fork. Chromatin restoration on nascent DNA is a complex and regulated process that includes nucleosome assembly and remodeling, deposition of histone variants, and the re-establishment of transcription factor binding. To study the genome-wide dynamics of chromatin restoration behind the DNA replication fork, we developed nascent chromatin occupancy profiles (NCOPs) to comprehensively profile nascent and mature chromatin at nucleotide resolution. Although nascent chromatin is inherently less organized than mature chromatin, we identified locus-specific differences in the kinetics of chromatin maturation that were predicted by the epigenetic landscape, including the histone variant H2AZ, which marked loci with rapid maturation kinetics. The chromatin maturation at origins of DNA replication was dependent on whether the origin underwent initiation or was passively replicated from distal-originating replication forks, suggesting distinct chromatin assembly mechanisms surrounding activated and disassembled prereplicative complexes. Finally, we identified sites that were only occupied transiently by DNA-binding factors following passage of the replication fork, which may provide a mechanism for perturbations of the DNA replication program to shape the regulatory landscape of the genome.
Subject(s)
Chromatin , DNA Replication , DNA, Bacterial/biosynthesis , Saccharomyces cerevisiae/genetics , Chromatin/chemistry , Chromatin Assembly and Disassembly , Chromosome Mapping , DNA-Binding Proteins/metabolism , Histones/metabolism , Nucleosomes/metabolism , Replication OriginABSTRACT
The association of environmental factors and child rearing practices with body mass index z-score (BMIZ) in children residents of Children's Homes from Floridablanca, Colombia was studied. A random sample of 176 preschool children aged 3-6 years was weighed and measured, their parents or caregiver were also measured and they answered a survey. The generalized linear model showed that BMIZ increased significantly with children's age (β=0.02), children's sex (male β=0.27), mother's occupation (homemaker β=0.29), mother's overweight (β=0.20), person who accompanies children while they eat (relatives β=0,49; anyone or non-relative β=0.40), person who cooks (grandmother β=0.55), adequate time spent on eating by children (β=0.54), and overeating (0.51). BMIZ decreased significantly with mother's occupation (looking for a job or student β=-0.43), maternal history of hypertension (β=-0.26), motivation to eat (β=-0.59) and pressure to eat (β=-0.55).
El objetivo del estudio fue determinar la asociación de factores ambientales y estilos de crianza con el puntaje z del Indice de Masa Corporal (IMCZ) en preescolares de los Hogares Infantiles de Floridablanca, Colombia. Una muestra aleatoria de 176 preescolares de 3 a 6 años fueron medidos y pesados; sus padres o cuidadores fueron medidos y respondieron una encuesta. El modelo lineal generalizado mostró que el IMCZ aumenta significativamente con la edad (β=0,02) y sexo del preescolar (masculino β=0,27), ocupación (ama de casa β=0,29) y sobrepeso de la madre (β=0,20), persona que lo acompaña mientras come (familiares β=0,49; ninguno o no familiares β=0,40), persona que prepara los alimentos (abuela β=0,55), comer en un tiempo adecuado (β=0,54), y comer demasiado (0,51). El IMCZ disminuye significativamente con la ocupación de la madre (buscando trabajo o estudianteβ=-0,43), antecedentes de hipertensión arterial maternos (β=-0,26), motivación para comer (β=-0,59), y presión para comer (β=-0,55).
