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A molecular model of chromatin organisation and transcription: how a multi‐RNA polymerase II machine transcribes and remodels the β‐globin locus during development
Author(s) -
Wong Hua,
Winn Peter J,
Mozziconacci Julien
Publication year - 2009
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.200900062
Subject(s) - transcription (linguistics) , rna polymerase ii , biology , genetics , chromatin , transcription bubble , rna polymerase ii holoenzyme , transcription factor ii f , general transcription factor , rna polymerase , gene , promoter , locus (genetics) , eukaryotic transcription , dna supercoil , microbiology and biotechnology , rna , gene expression , dna replication , philosophy , linguistics
Abstract We present a molecular model of eukaryotic gene transcription. For the β‐globin locus, we hypothesise that a transcription machine composed of multiple RNA polymerase II (PolII) assembles using the locus control region as a foundation. Transcription and locus remodelling can be achieved by pulling DNA through this multi‐PolII ‘reading head’. Once a transcription complex is formed, it may engage an active gene in several rounds of transcription. Observed intergenic sense and antisense transcripts may be the result of PolII pulling the DNA through the reading head whilst searching for the promoter of a gene. Support for this hypothesis is provided using various data from the literature. In the model, DNA is packed in a 30‐nm chromatin fibre, thus gene regulatory regions separated by kilobases are close in space. This, and the need to store transcription‐induced supercoiling, may explain why functionally interacting regions are often separated by many kilobases.