Chromatin is a term used to refer to a mix of histone, DNA as well as other proteins making up chromosomes. It is contained in eukaryotic cell’s nuclear envelope. Chromatin is divided into a condensed form known as heterochromatin and an extended form known as euchromatin. The euchromatin form participates in transcribing RNA, the component that helps in protein production for purposes of generating energy. This form of chromatin is usually more dispersed than the other form. The heterochromatin form is responsible for holing silent genes or genes that are less pronounced in gene expression. It holds the DNA that is said to be genetically inactive. The main function of chromatin is to organize DNA into smaller volume to enable it fit inside a cell. Chromatin also helps strengthen DNA in order to enable meiosis and mitosis, regulates gene expression and replication of DNA. Changes in the structure of chromatin are influenced by modification in chemicals in histone proteins like acetylation and methylation as well as other proteins that bind the DNA.
Importance of Chromatin
Chromatin performs various important functions. One of its key functions is to condense DNA to enable it fit within a cell nucleus. The length of a DNA is usually six feet. Some cells require more detailed packaging. These include red blood cells called avian and spermatozoa. The chromatin also aids in transcribing RNA and protects DNA from getting damaged as it is compacted into the nucleus. Chromatin is also important in gene expression. During a processes referred to as spermiogenesis, a component called spermatid found in the chromatin is remodeled to form a much spaced package, crystal like and widened structure. This process is related to the termination of transcription and has to do with the exchange of nuclear protein. In most cases, histones are displaced then replaced by tiny proteins that are rich in arginine called protamines.