Virus Hepatitis

VIRUS HEPATITIS | REVIEW

By Kisenda

Viral Structure

Hepatitis C virus is included in the family Flaviviridae, with spesification spherical, enveloped, single-stranded RNA virus. It is virus with approximately diameter 50 nm. This envelope structure is coverd with the protein spike. The RNA is a linear structure comprising of 9379 nucleotides which acts as a genome of this virus.The 5’terminal of the genome encodes envelop proteins and the structural capsid. The 3’ terminal is the funtional region and thus encodes RNA polymerase, regulatory proteins, and viral proteases. The RNA genome is a positive strand, encodes for a polyprotein of 3010 to 3030 amino acids. This protein undergoes proteolytic post-translational cleavage. Phosphorylated protein composes the capsid.

How this Virus Replicate

Hepatitis C Virus replicated in the hepatocytes cytoplasm. Following penetration stage, positive RNA strand first is translated to synthesize various structural proteins including RNA_dependent RNA polymerase. Using the positive strand as a template, RNA polymerase prepares the negative strand, or a complementary copy. This negative strand act as a replicative intermediate. And The RNA_dependent RNA polymerase using this structure as templete also synthesize positive strands. then, the virus is assembled which is realeased by budding process.

Hepatitis C Virus – Genetic Variation

Hepatitis C virus has a tendency to undergo genetic variation during replication process. This tendency has been related to the lack of proofreading mechanism for the newly synthesized RNA. Thus, this virus populations extremely heterogenous. Over the centuries, this persistent diversity has led to the development of several distinct groups of the virus. Now, Hepatitis C virus classified as six major subtypes. This is yet to be confirmed what role these genotypes or subtypes play in the severity of the disease. The ability of this virus to change its genotype character also occurs within the infected person, and creates a closely family related virus but with minor differences, called quasispecies. These minor changes will be its ability to escape the host’s immune surveillance. It is because antibody produced against one quasispecies often fail to against another quasispecies.

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