Histone variants at the transcription start-site.
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.
The John Curtin School of Medical Research, The Australian National University, PO Box 334, Canberra, ACT 2601, Australia.
Tatiana A
TA
Soboleva
The John Curtin School of Medical Research, The Australian National University, PO Box 334, Canberra, ACT 2601, Australia.
Maxim
M
Nekrasov
The John Curtin School of Medical Research, The Australian National University, PO Box 334, Canberra, ACT 2601, Australia.
Daniel P
DP
Ryan
The John Curtin School of Medical Research, The Australian National University, PO Box 334, Canberra, ACT 2601, Australia. Electronic address: david.tremethick@anu.edu.au.
David J
DJ
Tremethick
D000595:Amino Acid Sequence; D000818:Animals; D006657:Histones / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009707:Nucleosomes / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D024363:Transcription Initiation Site
D006657:Histones; D009707:Nucleosomes; D020033:Protein Isoforms
chromatin; histone variants; nucleosome mapping; transcription start site; transcriptional regulation; unstable nucleosomes