Re: Does one part of DNA ineract/communicate with the next?

Hi Dan,

As Cheshire Cat says, “We're all mad here. I'm mad. You're mad.”

But to answer your question, yes, in a manner of speaking, although the communications are mediated by proteins. As a bit of background, look at this schematic diagram of a gene:

http://nitro.biosci.arizona.edu/courses/EEB600A-2003/lectures/lecture24/figs/euk.jpg

The “coding sequence” or “coding region” portion of the gene has the information that is actually translated into the gene product. However, the expression of the gene is controlled by the portion known as the promoter, which is located right next to the coding sequence (the TATA box, shown separately in the diagram, is part of the promoter). Promoters contain several short regions that can be recognized and bound to by various proteins called transcription factors. If the right combination of transcription factors binds to the promoter, the gene will be expressed.

In addition to the promoter, “enhancers” also have an effect on the expression of some genes. A noteworthy difference between enhancers and promoters is that enhancers can be located much further away on the same strand of DNA (that is, the same chromosome), or even on a different chromosome.

If you think of DNA as a long flexible string, it’s easy to imagine that any part of that string could be made to touch any other part, simply by bending the string. In this way, the enhancer can be brought into contact with the promoter, as seen here:

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Promoter.html#enhancers

Alex Brands