Search results for "Histone genes"

Enhancer blocking activity located near the 3′ end of the sea urchin early H2A histone gene

1997

The sea urchin early histone repeating unit contains one copy of each of the five histone genes whose coordinate expression during development is regulated by gene-specific elements. To learn how within the histone repeating unit a gene-specific activator can be prevented to communicate with the heterologous promoters, we searched for domain boundaries by using the enhancer blocking assay. We focused on the region near the 3′ end of the H2A gene where stage-specific nuclease cleavage sites appear upon silencing of the early histone genes. We demonstrated that a DNA fragment of 265 bp in length, defined as sns (for silencing nucleoprotein structure), blocked the enhancer activity of the H2A…

Characterization of a nuclear factor associated to the chromatin of sea urchin histone genes

2007

Enhancer, chromatin insulator, non-coding RNA and α-histone gene expression during embryogenesis of the sea urchin Paracentrotus lividus.

2009

Core promoters and chromatin insulators (ins) may direct a transcriptional enhancer (enh) to prefer a specific promoter in complex genetic loci. Enh and ins flank the sea urchin Paracentrotus lividus α-histone H2A transcription unit in a tandem repeated cluster containing the five histone genes. In vivo competition assays of enh and ins functions reveal that the H2A enh-bound MBF-1 activator participates also in the expression of the H3 gene and that the sns5 ins buffers the downstream H1 promoter from the H2A enh. These results suggest that both the H2A enh and the sns5 ins may account for the diverse accumulation of the linker vs core nucleosomal histones during early development of the s…

Functional characterization of the enhancer blocking element of the sea urchin early histone gene cluster reveals insulator properties and three esse…

2000

Insulator elements can be functionally identified by their ability to shield promoters from regulators in a position-dependent manner or their ability to protect adjacent transgenes from position effects. We have previously reported the identification of a 265 bp sns DNA fragment at the 3' end of the sea urchin H2A early histone gene that blocked expression of a reporter gene in transgenic embryos when placed between the enhancer and the promoter. Here we show that sns interferes with enhancer-promoter interaction in a directional manner. When sns is placed between the H2A modulator and the inducible tet operator, the modulator is barred from interaction with the basal promoter. However, th…