DNA replication and transcription

[gfd43tg]

Hello,

I notice that when DNA is replicated, it is split apart. This is the same as the start of transcription, however I suppose the difference is that DNA is replicated with DNA polymerase, and RNA with RNA polymerase. Do these two polymerases compete for a strand of DNA in order to do their polymerization?

 

[Ygggdrasil]

Yes, they both compete for the same strand of DNA, which one might think would be problematic. Because replication and transcription are occurring at the same time in many cells, one could imagine collisions between the two polymerases causing traffic jams on the DNA. Bruce Alberts investigated what happens when RNA and DNA polymerases collide and found that DNA polymerase was surprisingly able to bypass RNA polymerases transcribing the same DNA that the DNA polymerase was trying to replicate (http://www.ncbi.nlm.nih.gov/pubmed/7855590). More recently, Mike O'Donnell's lab figured out some of the details about how this process occurs at the molecular level (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3918965/).

 

[gfd43tg]

Cool stuff, sounds like it is beyond the scope of my course. I just thought it strange how these two are introduced as if they happen in a vacuum