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The Set2 Histone Methyltransferase Functions through the Phosphorylated Carboxyl-terminal Domain of RNA Polymerase II
The histone methyltransferase Set2, which specifically methylates lysine 36 of histone H3, has been shown to repress transcription upon tethering to a heterologous promoter. However, the mechanism of targeting and the consequence of Set2-dependent methylation have yet to be demonstrated. We sought t...
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Published in: | The Journal of biological chemistry 2003-03, Vol.278 (11), p.8897-8903 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The histone methyltransferase Set2, which specifically methylates lysine 36 of histone H3, has been shown to repress transcription
upon tethering to a heterologous promoter. However, the mechanism of targeting and the consequence of Set2-dependent methylation
have yet to be demonstrated. We sought to identify the protein components associated with Set2 to gain some insights into
the in vivo function of this protein. Mass spectrometry analysis of the Set2 complex, purified using a tandem affinity method, revealed
that RNA polymerase II (pol II) is associated with Set2. Immunoblotting and immunoprecipitation using antibodies against subunits
of pol II confirmed that the phosphorylated form of pol II is indeed an integral part of the Set2 complex. Gst-Set2 preferentially
binds to CTD synthetic peptides phosphorylated at serine 2, and to a lesser extent, serine 5 phosphorylated peptides, but
has no affinity for unphosphorylated CTD, suggesting that Set2 associates with the elongating form of the pol II. Furthermore,
we show that set2 Î ppr2 Î double mutants ( PPR2 encodes TFIIS, a transcription elongation factor) are synthetically hypersensitive to 6-azauracil, and that deletions in
the CTD reduce in vivo levels of H3 lysine 36 methylation. Collectively, these results suggest that Set2 is involved in regulating transcription
elongation through its direct contact with pol II. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.M212134200 |