ABSTRACT
This chapter explains how DNA methyl-binding domains are able to interact with histone acetyltransferases and methyltransferases that can modify the structure of chromatin and prevent access of the transcriptional machinery to the DNA. This is only one method by which DNA sequence information can be used to position histone-modifying enzymes at the desired loci. The chapter shows how the assembly occurs in stages, with the delivery of the TATA box binding protein to the core promoter as part of the TFIID protein complex. Immunoprecipitation experiments show that p300-CBP co-precipitates with other proteins possessing strong histone methyltransferase activity that preferentially methylates lysines 4 and 9 on histone H3. The concept of “sweeping” chromatin proteins away from the DNA by passage of the transcription complex is one we have seen before in relation to chromatin remodeling, but this requires that the gene (or cluster of genes in the case of HOX) will have already been remodeled for activation by other mechanisms.
