Search results for " chromatin insulator"
showing 3 items of 3 documents
The Ambulacraria-specific COMPASS-like protein contributes to sns5 chromatin insulator function in the sea urchin embryo
2013
Promoter activity of the sea urchin (Paracentrotus lividus) nucleosomal H3 and H2A and linker H1 a-histone genes is modulated by enhancer and chromat…
2009
Core promoters and chromatin insulators are key regulatory elements that may direct a transcriptional enhancer to prefer a specific promoter in complex genetic loci. Enhancer and insulator flank the sea urchin (Paracentrotus lividus) alpha-histone H2A transcription unit in a tandem repeated cluster containing the five histone genes. This article deals with the specificity of interaction between the H2A enhancer-bound MBF-1 activator and histone gene promoters, and with the mechanism that leads the H1 transcripts to peak at about one-third of the value for nucleosomal H3 and H2A mRNAs. To this end, in vivo competition assays of enhancer and insulator functions were performed. Our evidence su…
The sea urchin histone H2A enhancer-binding protein MBF-1 is needed for maximal expression also for the H3 gene, while is buffered by the sns5 insula…
2009
Enhancers are DNA elements which increase the transcription of associated gene in a position and distance independent manner relative to the transcription initiation site. Molecular mechanisms must operate to direct enhancers to specific promoters in complex genetic loci. The sea urchin a-histone genes are organized in several hundred tandem repeated units, each containing one copy of the five histone genes in the order 5’-H4-H2B-H3-H2A-H1-3’. Transcription is limited to the early cleavage and reaches its maximum at morula stage. After hatching these genes are repressed and maintained in the silenced state for whole life cycle of the animal. In Paracentrotus lividus, the MBF-1 activator bin…