cccDNA

The cccDNA (from tight. Covalently closed circular DNA) is a special DNA structure that occurs during propagation of some viruses in the cell nucleus, where it can remain permanently. The cccDNA is a double-stranded DNA, which has been transferred from a linear shape by using a DNA ligase to covalently closed ring. Most can only take from this cccDNA transcription of the viral mRNA. CccDNA the virus is also referred to as episomal DNA, or as infrequently minichromosome.

Properties

The existence of cccDNA during propagation distinguishes the non- taxonomic group of " real" retroviruses ( retroviruses ) of the para- retroviruses. While the former integrate the DNA intermediate by ligation into the genome of the cell, the DNA level Para retroviruses remains as episomal cccDNA in the nucleoplasm.

The cccDNA was first described in DNA bacteriophages, but also found in certain cell cultures in which infection with DNA viruses ( polyomaviruses ) was detected later. CccDNA is typical of the members of the virus family Hepadnaviridae and Caulimoviridae such as hepatitis B virus (HBV). HBV in the cccDNA is formed from a linear DNA bound to the capsid, after removal of the bound DNA, the viral polymerase. In HBV infection, cccDNA remains even in the classical clinical cure of infection in the liver cells and can therefore rarely result in reactivation. The amount of cccDNA is also considered a marker for HBV therapy.

Swell

• Virology
• DNA
• Abbreviation