Polymerase stalling gets genes in sync

Access through your institution Buy or subscribe Chance differences in the recruitment of RNA polymerase II (RNAPII) to promoters are a key source of stochasticity in eukaryotic gene

expression. One way to decrease this variability might be through the pre-loading of RNAPII at promoters so that target genes are poised for simultaneous activation in different cells.

Boettiger and Levine investigated this possibility in the context of _D. melanogaster_ embryogenesis, which, with its rapid transitions between gene expression patterns, provides a good

setting for exploring mechanisms of transcriptional precision. The authors carried out _in situ_ hybridization to analyse target genes of key developmental regulatory proteins using probes

that corresponded to intronic regions and could therefore detect nascent transcripts. To get a clear picture of the variability between cells in the timing of transcriptional onset, they

used a semi-automated computational method to obtain quantitative measures of gene expression in large numbers of embryos. By looking at genes that are activated at a range of times and

positions during embryogenesis, Boettiger and Levine distinguished two classes of developmental genes: the first class showed synchronous expression, in which all of the cells began to

express the transcript within a short time frame (2–3 minutes), whereas the second class showed stochastic onset, in which transcriptional activation occurred over a much longer period

(sometimes more than 20 minutes) in different cells. These two classes had not been distinguished before, probably because of the smaller numbers of embryos examined in previous studies.

Strikingly, the genes that showed synchronous expression were associated with stalled RNAPII, whereas the genes that showed stochastic onset were not. This is a preview of subscription

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ACCESS OPTIONS: * Log in * Learn about institutional subscriptions * Read our FAQs * Contact customer support ORIGINAL RESEARCH PAPER * Boettiger, A. N. & Levine, M. Synchronous and

stochastic patterns of gene activation in the _Drosophila_ embryo. _Science_ 325, 471–473 (2009) Article  CAS  Google Scholar  Download references Authors * Louisa Flintoft View author

publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Flintoft, L. Polymerase stalling

gets genes in sync. _Nat Rev Genet_ 10, 591 (2009). https://doi.org/10.1038/nrg2656 Download citation * Issue Date: September 2009 * DOI: https://doi.org/10.1038/nrg2656 SHARE THIS ARTICLE

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