Influence of Rotational Nucleosome Positioning on Transcription Start Site Selection in Animal Promoters

PLoS Comput Biol. 2016 Oct 7;12(10):e1005144. doi: 10.1371/journal.pcbi.1005144. eCollection 2016 Oct.

Abstract

The recruitment of RNA-Pol-II to the transcription start site (TSS) is an important step in gene regulation in all organisms. Core promoter elements (CPE) are conserved sequence motifs that guide Pol-II to the TSS by interacting with specific transcription factors (TFs). However, only a minority of animal promoters contains CPEs. It is still unknown how Pol-II selects the TSS in their absence. Here we present a comparative analysis of promoters' sequence composition and chromatin architecture in five eukaryotic model organisms, which shows the presence of common and unique DNA-encoded features used to organize chromatin. Analysis of Pol-II initiation patterns uncovers that, in the absence of certain CPEs, there is a strong correlation between the spread of initiation and the intensity of the 10 bp periodic signal in the nearest downstream nucleosome. Moreover, promoters' primary and secondary initiation sites show a characteristic 10 bp periodicity in the absence of CPEs. We also show that DNA natural variants in the region immediately downstream the TSS are able to affect both the nucleosome-DNA affinity and Pol-II initiation pattern. These findings support the notion that, in addition to CPEs mediated selection, sequence-induced nucleosome positioning could be a common and conserved mechanism of TSS selection in animals.

MeSH terms

  • Base Sequence
  • Binding Sites
  • Computer Simulation
  • DNA / genetics*
  • Models, Genetic
  • Molecular Sequence Data
  • Nucleosomes / genetics*
  • Promoter Regions, Genetic / genetics*
  • RNA Polymerase II / genetics*
  • Transcription Initiation Site / physiology*
  • Transcription, Genetic / genetics*
  • Transcriptional Activation / genetics

Substances

  • Nucleosomes
  • DNA
  • RNA Polymerase II

Grants and funding

This work was supported by the Swiss Government and the Swiss National Science Foundation [31003A_125193 to GA]. http://www.snf.ch/en/Pages/default.aspx. Funding for open access charge: Swiss Government. http://www.admin.ch. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.