Repression of Plant Gene Expression via Chromosomal Remodelling Using Histone Deacetylases

Posttranscriptional modification of nucleosomal histones is an important mechanism in the regulation of eukaryotic gene expression. Acetylation and deacetylation is a major process of such regulation. Acetylation of the histones by acetyltransferases leads to a relaxed status of the chromosomes, and thus, enhances accessibility of transcription components to the promoters and activates the gene expression. Deacetylation of histones by histone deacetylases (HDACs) remove acetyl groups from the core histones, which results in chromatin condensation and restricts access of the transcription machinery to gene regulatory elements. This leads to the repression of transcription (Landry et al., 2000; Murfett et al., 2001). Several different types of HDACs have been identified in eukaryotic organism (Dangl et al., 2001). Plants possess a unique type of HDACs, namely, the HD2 family. HD2 family is not related to other classes of HDACs