A closer look is taken at gene transcription in living organisms in a paper published online by Nature Structural & Molecular Biology. Transcription by RNA polymerase II, the enzyme that transcribes DNA into messenger RNAs, is at the core of gene expression and is a major focus of biological regulatory mechanisms. Much of what is known about transcription comes from test tube experiments (in vitro) studies with purified components but little is known about how RNA polymerase works in vivo.
Robert Singer and co-workers have now taken the analysis of the mechanism of gene transcription in higher organisms to a new level by using advanced fluorescence imaging techniques to measure quantitatively the kinetics of gene transcription by RNA polymerase II in living mammalian cells. The ultimate goal of this work is a quantitative model of gene transcription in vivo. They find several novel and unexpected features concerning the nature of the in vivo transcription.
First, they conclude that only a surprisingly small fraction of RNA polymerases that bind to the start of a gene, amounting to about 1%, actually go on to transcribe the gene and produce a messenger RNA. Second, they find that RNA polymerases transcribe more rapidly than previously thought, often pausing for prolonged periods. This study represents a critical milestone on the way to building a quantitative understanding of the mechanism of transcription in single live cells.
Robert Singer (Albert Einstein College of Medicine, New York, NY, USA)
Abstract available online.
(C) Nature Structural & Molecular Biology press release.
Message posted by: Trevor M. D'Souza