1.   And when those viral genes are activated, the cell starts producing more HIV.

2.   Besides the human Factor IX gene, the Avigen virus carries a piece of DNA that signals the cell to activate the gene and make its product.

3.   But they can tell from its structure that it is a master switch whose role is to activate other genes.

4.   Cells usually activate genes by having an agent known as a promoter attach itself to a stretch of DNA just upstream of a target gene.

5.   Dymecki found she had knocked out the DNA sequence activating a gene called BMPRIB, which evidently contains the genetic information that sculpts cartilage into digits.

6.   Fiber also favorably changes the balance of microorganisms that live in the gut and may even activate a gene that protects against cancer.

7.   Further ahead, lies the possibility of developing drugs to shut telomerase down in the many kinds of cancer cells that activate the gene.

8.   Now that researchers know exactly how the genes can be activated, said Tilly, there is the potential taht they can be deactivated.

9.   Since the cell cuts out and discards the introns when a gene is activated, these disposable pieces of DNA have long been ignored.

10.   That gene is turned on by exposure to dioxin, he said, so drug companies become wary if a drug they are developing activates that gene.