Hepatitis C is a flaviviros, a member of the same family as the viruses that cause yellow fever and dengue fever. Like those viroses, it has a genome that consists of a single strand of RNA.

When a hepatitis C virus enters your bloodstream, it seeks out a liver cell. This is the only place in your body where it can reproduce. One particular protein on its shell, called the E2 protein, attaches itself to the outside of a liver cell at a place called a receptor site. Then the protein core of the virus penetrates the cell’s wall. It does this chemically, by merging its lipid coat with the cell wall. Once fused like this, the cell wall surrounds and engulfs the virus, bringing it inside. Now inside the cell, the virus can release its load of viral RNA and begin its work of reproducing its genetic material.

Inside the cell, the virus’s coat dissolves and releases viral RNA that then takes over parts of the cell-the ribosomes to manufacture the material it needs for reproduction. In a sense, the virus “fools” the cell into treating the viral RNA as if it were its own. During this process, the virus either shuts down the normal functions of the cell or forces it to make more infected cells (which may be why the virus is associated with liver cancer). Now the viral RNA begins to copy itself billions of times, creating the material for new viruses. The large number of reproductive processes going on gives ample opportunity for genetic mutations, creating the RNA for new strains and subtypes of the hepatitis C virus. An infected person can produce 1,000 billion copies of hepatitis C virus per day.

Finally, the viral RNA creates capsomeres, the stuff of which the virus’s protein coat is made. These capsomeres fit together like building blocks, eventually forming a shell called a capsid. This material encapsulates the viral RNA in a spherical form, creating a new virus. The liver cell cooperates by providing the virus with a protective lipid coat and then releasing it to start the cycle all over again, attacking another liver cell. This goes on repeatedly at the cell’s surface, until the cell dies.

The process includes the production of certain enzymes, called protease, helicase and polymerase enzymes, that are essential in the virus’s reproduction. The structure of these enzymes is well-known, and this knowledge is the first step in designing a drug to attack them and thus interfere with the virus’s reproduction.

Tagged under:bloodstream dengue fever Diseases genetic material genome hepatitis c virus liver cell protein core viral rna yellow fever

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Filed under: Diseases