Methylation of RNA polymerase II non-consensus lysine residues marks early transcription in mammalian cells

Dias, João D, Rito, Tiago, Torlai Triglia, Elena, Kukalev, Alexander, Ferrai, Carmelo, Chotalia, Mita, Brookes, Emily, Kimura, Hiroshi and Pombo, Ana (2015) Methylation of RNA polymerase II non-consensus lysine residues marks early transcription in mammalian cells. eLife. (doi:10.7554/eLife.11215).

Abstract

Dynamic post-translational modification of RNA polymerase II (RNAPII) coordinates the co-transcriptional recruitment of enzymatic complexes that regulate chromatin states and the processing of nascent RNA. Extensive phosphorylation of serine residues at the largest RNAPIIsubunit occurs at its structurally-disordered C-terminal domain (CTD), which is composed of multiple heptapeptide repeats with consensus sequence Y1-S2-P3-T4-S5-P6-S7. Serine-5 and Serine-7 phosphorylation mark transcription initiation, whereas Serine-2 phosphorylation coincides with productive elongation. In vertebrates, the CTD has eight non-canonical substitutions of Serine-7 into Lysine-7, which can be acetylated (K7ac). Here, we describe mono- and di-methylation of CTDLysine-7 residues (K7me1 and K7me2). K7me1 and K7me2 are observed during the earliest transcription stages and precede or accompany Serine-5 and Serine-7 phosphorylation. In contrast, K7ac is associated with RNAPII elongation, Serine-2 phosphorylation and mRNA expression. We identify an unexpected balance between RNAPII K7 methylation and acetylation at gene promoters, which fine-tunes gene expression levels

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Contributors

Author: Emily Brookes

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