Sunday, November 11, 2007

A Most Scurvy Monster

I tried to look at the thing in a scientific spirit and soon my mind was filled with one thought, one conception:"Uniting of godly and devilish elements" resounded within me. Here was something for my thoughts to cling to. This idea was familiar to me from conversations with Demian. During the last period of our friendship he had said that we had been given a god to worship who represented only one arbitrarily separated half of the world (it was the official, sanctioned, luminous world), but that we ought to be able to worship the whole world; this meant that we would either have to have a god who was also a devil or institute a cult of the devil alongside the cult of god. And now Abraxas was the god who was both god and devil.

Animal viruses are usually content to remain aloof within the nucleus they invade, using the host cell's machinery to replicate themselves, but seldom mingling with the local DNA. Retroviruses work backward. They have no DNA. Their genetic instructions are coded in RNA. Like all viruses, they carry none of the other requirements for life—such as manufacturing, processing, or reproductive equipment—just a genetic blueprint sealed in a protective capsule. For the rest they must depend on the cell they infect. But a cell is not set up to process genetic instructions in RNA.





The first thing a retrovirus does when it gets inside a cell and takes off its protective coat is make a copy of itself in DNA.Retroviruses are so-called because they possess a unique cellular enzyme, reverse transcriptase, which uses the viral RNA as a template to make a DNA copy. The DNA copy of the virus then slices open a host chromosome, inserts itself, and in a kind of inner colonialization, becomes for all intents and purposes one of the cell's own genes. When the cell begins transcribing this viral DNA sequence into RNA—as it must to get a working copy of any gene for use in protein production—the result is more copies of the RNA virus and the orders for materials needed to make the virus capsules.

To paraphrase Shakespeare, retroviruses are such stuff as nightmares are made of. But they are also the stuff of wonder.That's most certain.Now part of the cell's chromosome, the virus—that is, all that's left of it, its genes—is in the catbird seat.To take an analogy from history: invading conquerors let us use the French colonialists in Indochina as an example, set out to govern a conquered country, not according to the judicial system which they find in force there, but according to their own.Like any good DNA, the viral genes may transcribe messenger RNA, which travels back into the cytoplasm, some of it directing the cells' ribosomes to manufacture new viral proteins, some of it becoming enveloped by the emerging viruses to form their new cores of RNA.

Or the integrated viral DNA may exert its influence upon the cellular genome and cause the cell to reproduce aberrantly, erratically, uncontrollably, thereby transforming it into a malignant cell. Or the viral genes may do nothing at all, may simply lie low—for years, perhaps—safe and undetected within the heart of the cell, until prompted once again to become active and produce more viruses, or a transformed cell, or both. What causes the activation isn't always entirely clear. There are many retroviral mysteries to be unraveled.

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