The Molecules of HIV

Note: this site last updated in 2006

HIV can activate a cancer-causing gene

An article from "The Molecules of HIV" (c) Dan Stowell

The HIV virus inserts its genes into the host cell's genome, essentially at an arbitrary position along the genome. (That is: the virus doesn't take special care to insert its genes at any specific point.) Sometimes this makes no particular difference to the host's genes, but sometimes it upsets the way genes are regulated.

Many genes are regulated by short stretches of code which sit nearby, which can encourage or suppress the expression of those genes by affecting the likelihood that transcription enzymes will attach to that stretch of genome.

In most cells certain genes (such as growth factors which encourage cell proliferation) must be "switched off" for the cell's normal operation. If the mechanism for switching-off the gene is interrupted, for example by the viral genome being spliced into the middle of the regulatory code, then a cell's behaviour may change. If, for example, a growth factor starts to be produced, this can cause uncontrolled cell multiplication, which could result in a tumour, or cancer.

A tumour-causing gene is called an oncogene. A gene which could be turned into an oncogene (as described above) is called a proto-oncogene. More information about oncogenes

Written by
Dan Stowell

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