Replication of the Chicken β-Globin Locus: Early-Firing Origins at the 5′ HS4 Insulator and the ρ- and βA-Globin Genes Show Opposite Epigenetic Modifications

• DOI: 10.1128/mcb.23.10.3536-3549.2003
• Publication Date: 2003-05-01T02:00:00Z
• Authors: Marie-Noëlle Prio...; Marie-Claude Gendron; Olivier Hyrien
• Keywords: 0301 basic medicine; Time Factors; Models, Genetic; Reverse Transcriptase Polymerase Chain Reaction; Folate Receptors, GPI-Anchored; Receptors, Cell Surface; DNA; DNA Methylation; Chromatin; Globins; Protein Structure, Tertiary; S Phase; 3. Good health; Histones; 03 medical and health sciences; Bromodeoxyuridine; Animals; CpG Islands; Carrier Proteins; Chickens; DNA Primers; Protein Binding

Chromatin structure is believed to exert a strong effect on replication origin function. We have studied the of chicken β-globin locus, whose chromatin has been extensively characterized. This locus delimited by hypersensitive sites (HSs) that mark position insulator elements. A stretch condensed and another HS separate domain from an adjacent folate receptor (FR) gene. demonstrate here in erythroid cells express FR but not globin genes, initiates at four within domain, one 5′ HS4 other three near ρ- βA-globin genes. Three origins consist G+C-rich sequences enriched CpG dinucleotides. The fourth A+T rich. Together with previous work, these data reveal unmethylated CpGs, hyperacetylated histones H3 H4, lysine 4-methylated histone H3. In contrast, opposite modifications are observed origins. also show whole region, including chromatin, replicates early S phase cells. Therefore, different early-firing same may patterns epigenetic modifications. role elements DNA discussed.