Article

Pol II waiting in the starting gates: Regulating the transition from transcription initiation into productive elongation

Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
Biochimica et Biophysica Acta (Impact Factor: 4.66). 11/2010; 1809(1):34-45. DOI: 10.1016/j.bbagrm.2010.11.001
Source: PubMed

ABSTRACT Proper regulation of gene expression is essential for the differentiation, development and survival of all cells and organisms. Recent work demonstrates that transcription of many genes, including key developmental and stimulus-responsive genes, is regulated after the initiation step, by pausing of RNA polymerase II during elongation through the promoter-proximal region. Thus, there is great interest in better understanding the events that follow transcription initiation and the ways in which the efficiency of early elongation can be modulated to impact expression of these highly regulated genes. Here we describe our current understanding of the steps involved in the transition from an unstable initially transcribing complex into a highly stable and processive elongation complex. We also discuss the interplay between factors that affect early transcript elongation and the potential physiological consequences for genes that are regulated through transcriptional pausing.

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    • "Subsequently, this transcription bubble is unwound to approximately 18–25 bases, and a short DNA-RNA hybrid is synthesized. Transcripts of ten or more nucleotides result in promoter escape and stabilization of a mature bubble (Liu et al., 2011; Luse, 2013; Nechaev and Adelman, 2011). The number of nucleotides unwound in a mature bubble is still a matter of debate, since sizes ranging from 8 to 22 nucleotides have been reported for bacterial, archaeal, and eukaryotic polymerases (Fiedler and Timmers, 2001; Naryshkin et al., 2000; Pal et al., 2005). "
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