Abstract
Efficient transcription of RNA polymerase II (Pol II) through nucleosomes requires the help of various factors. Here we show biochemically that Pol II transcription through a nucleosome is facilitated by the chromatin remodeler Chd1 and the histone chaperone FACT when the elongation factors Spt4/5 and TFIIS are present. We report cryo-EM structures of transcribing Saccharomyces cerevisiae Pol II-Spt4/5-nucleosome complexes with bound Chd1 or FACT. In the first structure, Pol II transcription exposes the proximal histone H2A-H2B dimer that is bound by Spt5. Pol II has also released the inhibitory DNA-binding region of Chd1 that is poised to pump DNA toward Pol II. In the second structure, Pol II has generated a partially unraveled nucleosome that binds FACT, which excludes Chd1 and Spt5. These results suggest that Pol II progression through a nucleosome activates Chd1, enables FACT binding and eventually triggers transfer of FACT together with histones to upstream DNA.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Chromatin / genetics
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Chromatin / ultrastructure
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Chromatin Assembly and Disassembly
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / ultrastructure*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / ultrastructure*
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High Mobility Group Proteins / genetics
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High Mobility Group Proteins / ultrastructure*
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Histones / genetics
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Multiprotein Complexes / genetics
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Multiprotein Complexes / ultrastructure
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Nucleosomes / genetics
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Nucleosomes / ultrastructure
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RNA Polymerase II / genetics
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RNA Polymerase II / ultrastructure
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / ultrastructure
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / ultrastructure*
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Transcription, Genetic*
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Transcriptional Elongation Factors / genetics
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Transcriptional Elongation Factors / ultrastructure*
Substances
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CHD1 protein, S cerevisiae
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Chromatin
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Chromosomal Proteins, Non-Histone
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DNA-Binding Proteins
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FACT protein, S cerevisiae
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High Mobility Group Proteins
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Histones
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Multiprotein Complexes
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Nucleosomes
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Saccharomyces cerevisiae Proteins
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Transcriptional Elongation Factors
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SPT5 transcriptional elongation factor
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RNA Polymerase II