Histones expression affected

There are ways of modifying all the four bases of DNA chemically and of modifying the proteins bound to them, such as histones, which affect expression. Modification is environment dependent, e.g. availability of modifying agents. 

Fig. 10.2. FSPIM analysis of the interaction between maize transcriptional coactivators—GCN5 and ADA2—fused to CFP and YFP. GCN5 is a histone acetyltransferase that, in conjunction with adaptor protein ADA2, modulates transcription in diverse eukaryotes by affecting the acetylation status of the core histones in nucleosomes [63]. CFP- and YFP-tagged proteins, expressed in protoplasts, were excited by the 458 nm and the 514 nm laser lines sequentially. CFP fluorescence was selectively detected by an FIFT 458 dichroic mirror and BP 470-500 band pass emission filter while YFP fluorescence was selectively detected by using an HFT 514 dichroic mirror and...

In addition to its hydrolase activity with maximal velocity at acidic pH, biotinidase also possesses biotinyl-transferase activity at physiological pH, resulting in the biotinylation of nucleophilic compounds such as histones [13]. This activity may play an important role in the regulation of gene expression [30]. Both hydrolase and transferase activities are affected in patients with biotinidase deficiency [13]. 

Chromatin is the complex combination of DNA, RNA and protein that makes up chromosomes inside the nuclei of eukaryotic cells it is divided between heterochromatin (condensed) and euchromatin (extended) forms. The functions of chromatin are to package DNA into a smaller volume to fit into the cell, to support the DNA to allow mitosis and meiosis, and to serve as a mechanism to control expression and DNA replication. Changes in chromatin strncture are affected by chemical modifications of histone proteins, such as methylation (DNA and proteins) and acetylation (proteins), and by non-histone DNA-binding proteins. Chromatin is easily visualised by staining, hence its name, which literally means coloured, lightened material. 

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