DMMC Course: UNRAVELLING CHROMATIN & THE ROLE OF EPIGENETICS IN DISEASE

1400-1430 Tuesday 25 April 2006. UCD Conway Institute Lecture Theatre

Assessing histone modification in the laboratory
Emmett McArdle (UCD Conway Institute of Biomolecular & Biomedical Research)

Histone proteins comprise the structural scaffold that organizes the genome. Two each of the class H2A, H2B, H3 and H4 assemble to form one octameric nucleosome core particle by wrapping 146 base pairs of DNA. The H3 and H4 histones have long N-terminal tails protruding from the nucleosome which are rich in basic lysine and arginine amino acids that can be covalently modified by methylation, acetylation and phosphorylation. Acetylation of the H3 and H4 histones induces weak internucleosomal interactions and dissociation from DNA, facilitating transcription factor access to the promoter regions of genes. The chromatin immunoprecipitation (ChIP) assay using anti-acetyl-histone antibodies provides a direct experimental approach to assess the activation status of a gene promoter. ChIP using anti-acetyl-histone antibodies can serve as a valuable tool for studying nuclear events involved in the processing of DNA, prior to transcription factor binding and gene expression. This lecture deals with assessing histone acetylation using the ChIP assay as an approach to show gene promoter activation, as a prerequisite to assessing transcription factor binding in the lab.