Chromatin decondensation and nuclear reorganization of the HoxB locus upon induction of transcription

AUTOR(ES)

Chambeyron, Séverine

FONTE

Cold Spring Harbor Laboratory Press

RESUMO

The colinearity of genes in Hox clusters suggests a role for chromosome structure in gene regulation. We reveal programmed changes in chromatin structure and nuclear organization upon induction of Hoxb expression by retinoic acid. There is an early increase in the histone modifications that are marks of active chromatin at both the early expressed gene Hoxb1, and also at Hoxb9 that is not expressed until much later. There is also a visible decondensation of the chromatin between Hoxb1 and Hoxb9 at this early stage. However, a further change in higher-order chromatin structure, looping out of genes from the chromosome territory, occurs in synchrony with the execution of the gene expression program. We suggest that higher-order chromatin structure regulates the expression of the HoxB cluster at several levels. Locus-wide changes in chromatin structure (histone modification and chromatin decondensation) may establish a transcriptionally poised state but are not sufficient for the temporal program of gene expression. The choreographed looping out of decondensed chromatin from chromosome territories may then allow for activation of high levels of transcription from the sequence of genes along the cluster.

Documentos Relacionados

• Vertebrate HoxB gene expression requires DNA replication
• A structure of potentially active and inactive genes of chicken erythrocyte chromatin upon decondensation.
• Induction of RNA-directed DNA methylation upon decondensation of constitutive heterochromatin
• Cooperative DNA binding of the human HoxB5 (Hox-2.1) protein is under redox regulation in vitro.
• HoxB5 Is an Upstream Transcriptional Switch for Differentiation of the Vascular Endothelium from Precursor Cells