Somatic Recombination, Part 1: Immunology; saving and speaking of life

In a short series of posts, I will introduce an immune system process with the impressive title; Somatic Recombination, or, in this context, V(D)J Recombination. This process is significant for many reasons outside its critical and sole function; to build receptors. These receptors, also called antibodies, or Immunoglobulins, are capable of recognizing bits and pieces of invading pathogens and other substances that might harm the body. Of particular significance, the building process has potentially dangerous ends because it includes not only the cutting out and elimination of sections of an individuals DNA, but also the intentional introduction of mutations into the recombined DNA strands. Also, the process, when viewed across many Immune System cells, is an example of selection. It is not the same, of course, as natural selection occurring at a macroscopic level, but at the basic level, it does as it involves the survival and proliferation of those cells with receptors containing the sequence of amino acids that will best bind to a given antigen; the name given to the bits and pieces which stimulate our immune system into action.

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Somatic Recombination: Part 2, Transmembrane Receptors

The ability of a cell to sense its environment and receive information from other cells is central to the health and function of virtually every cell in the human body. The information obtained by a cell at its surface will induce signals within the cytoplasm that end in a variety of effects including cell motility (movement), maturation, and even death. Contrary to the static picture of cells, save neurons, from the biology texts of my youth, cells are dynamic and interactive. Further, this interactivity is critical not only to the health of the cell but the organism as well. Errors in intracellular signaling have been shown to play a role in cancer as well as many other conditions.

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Somatic Recombination Part 3: Odd Genes, Viral Action

Given negative light in which viruses are seen, it seems ironic then that the mechanism by which a retrovirus integrates its genetic material into the infected cell is very similar to the mechanism by which our B and T cells produce the molecules needed to recognize and defeat bacterial and viral infections. Two proteins, named RAG1 and RAG2, which start off the process in our cells, have been shown to form what is known as a transposase. In retroviruses such as the one which causes AIDS, a transposase is used to splice the viral genetic material into that of the infected cell. RAG1 & 2 combined in a human cell can do the exact same thing

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Somatic Recombination Part 4: Cutting up your DNA

So you’ve been told that all the cells in your body contain the same genetic material? I’ve seen it written as a general principle of Genetics and a quick search around the web will yield many sources indicating that all somatic cells contain the exact same DNA. I did find a few articles in science magazines which “revealed” that this may not be the case, but the general consensus that they do was prevalent.

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