The science of Viral Replication (COVID-19)
Please bear with me on this section. Read patiently for a full grasp because it will help you understand the rationale for specific drugs being tested.
To understand viral replication, you must understand human cell division and replication first. Human cells have a nucleus where double stranded DNA material is stored in the form of ladder like sophisticated tangles called chromosomes. For cell division and replication to occur, DNA has to be ‘transcribed’ into double stranded RNA and then ‘translated’ into amino acids which assemble to form proteins. These proteins are the workhorse of our body. They form the structural backbone of the cells; they become receptors; they are engaged in metabolism, and in body defense, and all that makes us go.
Any organism including a virus that wants to invade a human body must be able to exploit the machinery of the human cell assembly line for its own reproduction.
COVID-19 is a single stranded positive sense RNA virus. Most viruses are RNA viruses. So to embed themselves in human cells, they have to be able to enter human cells, then fool the human cell machinery to translate their own RNA to form viral proteins called virions. The virions assemble to become billions of newly formed viruses.
Being single stranded ‘positive’ sense, the SARs- Cov-2 virus has its own RNA polymerase enzyme which reduces it’s dependence on human RNA polymerase to make mRNA. So once inside the human cell, the initial step in replication of the virus is already easier for the Sars-cov-2 virus. But it must pass a few hurdles to enter the cell first. The virus must have the right surface protein and bind to a specific receptor on the human cell. In the case of Sars-Cov-2 the spike protein binds to the ACE-2 receptor of the alveolar cells of the lung.
To do all this, the virus must first be able to also escape detection by the powerful defense system of the body. And unfortunately, it can.
Stay tuned for the next chapter of how it achieves that feat . More to come. Promise it is very interesting.
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