Histone variants at the transcription start-site

Trends Genet. 2014 May;30(5):199-209. doi: 10.1016/j.tig.2014.03.002. Epub 2014 Apr 23.


The function of a eukaryotic cell crucially depends on accurate gene transcription to ensure the right genes are expressed whereas unrequired genes are repressed. Therefore, arguably, one of the most important regions in the genome is the transcription start-site (TSS) of protein-coding and non-coding genes. Until recently, understanding the mechanisms that define the location of the TSS and how it is created has largely focused on the role of DNA sequence-specific transcription factors. However, within the nucleus of a eukaryotic cell, transcription occurs in a highly compacted nucleosomal environment, and it is becoming clear that accessibility of the TSS is a key controlling step in transcriptional regulation. It has traditionally been thought that transcription can only proceed once the nucleosomes at the TSS have been evicted. New work suggests otherwise, however, and the focus of this review is to challenge this belief.

Keywords: chromatin; histone variants; nucleosome mapping; transcription start site; transcriptional regulation; unstable nucleosomes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Histones / chemistry
  • Histones / metabolism*
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Nucleosomes / metabolism
  • Promoter Regions, Genetic
  • Protein Isoforms / chemistry
  • Protein Isoforms / metabolism
  • Transcription Initiation Site*


  • Histones
  • Nucleosomes
  • Protein Isoforms