Synergistic action of RNA polymerases in overcoming the nucleosomal barrier

Jing Jin, Lu Bai, Daniel S Johnson, Robert M Fulbright, Maria L Kireeva, Mikhail Kashlev, Michelle D Wang
2010 Nature Structural & Molecular Biology  
During gene expression, RNA polymerase (RNAP) encounters a major barrier at a nucleosome and yet must access the nucleosomal DNA. Previous in vivo evidence has suggested that multiple RNAPs might increase transcription efficiency through nucleosomes. Here we have quantitatively investigated this hypothesis using Escherichia coli RNAP as a model system by directly monitoring its location on the DNA via a single-molecule DNA-unzipping technique. When an RNAP encountered a nucleosome, it paused
more » ... h a distinctive 0-base pair periodicity and backtracked by ~0-5 base pairs. When two RNAPs elongate in close proximity, the trailing RNAP apparently assists in the leading RNAP's elongation, reducing its backtracking and enhancing its transcription through a nucleosome by a factor of 5. Taken together, our data indicate that histone-DNA interactions dictate RNAP pausing behavior, and alleviation of nucleosome-induced backtracking by multiple polymerases may prove to be a mechanism for overcoming the nucleosomal barrier in vivo.
doi:10.1038/nsmb.1798 pmid:20453861 pmcid:PMC2938954 fatcat:elb6p7f2grgpxai75riohuyagq