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. Author manuscript; available in PMC: 2013 Oct 1.
Published in final edited form as: Nat Rev Genet. 2012 Oct;13(10):720–731. doi: 10.1038/nrg3293

Figure 2. Patterns of Pol II distribution across gene regions.

Figure 2

Pol II ChIP-seq signal is shown at genes that exemplify a variety of Pol II distributions that are observed across metazoan genomes. Example genes are taken from Drosophila S2 cells7, and the pausing index of each gene is indicated.
  1. Two paused, but active genes with differing pausing indices
  2. A paused but inactive gene
  3. A Non-paused gene that is expressed
  4. A Non-paused, unexpressed gene. We note that a pausing index cannot reliably be calculated for genes that lack significant Pol II promoter signal.
  5. Shown are profiles of Pol II signal that exemplify the four major groups of genes. We note that the “paused, unexpressed” group is significantly under-represented in vivo, suggesting that most paused genes display some basal RNA synthesis. Approximate percentages of genes that fall into each category are given2, 5, 28.