Tyrosine phosphorylation of RNA polymerase II CTD is associated with antisense promoter transcription and active enhancers in mammalian cells

• Main Authors: Nicolas Descostes, Martin Heidemann, Lionel Spinelli, Roland Schüller, Muhammad Ahmad Maqbool, Romain Fenouil, Frederic Koch, Charlène Innocenti, Marta Gut, Ivo Gut, Dirk Eick, Jean-Christophe Andrau
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2014-05-01
• Series: eLife
• Subjects: RNA polymerase II; carboxyl terminal domain; antisense transcription; enhancer; initiation; transcription
• Online Access: https://elifesciences.org/articles/02105

In mammals, the carboxy-terminal domain (CTD) of RNA polymerase (Pol) II consists of 52 conserved heptapeptide repeats containing the consensus sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. Post-translational modifications of the CTD coordinate the transcription cycle and various steps of mRNA maturation. Here we describe Tyr1 phosphorylation (Tyr1P) as a hallmark of promoter (5′ associated) Pol II in mammalian cells, in contrast to what was described in yeast. Tyr1P is predominantly found in antisense orientation at promoters but is also specifically enriched at active enhancers. Mutation of Tyr1 to phenylalanine (Y1F) prevents the formation of the hyper-phosphorylated Pol IIO form, induces degradation of Pol II to the truncated Pol IIB form, and results in a lethal phenotype. Our results suggest that Tyr1P has evolved specialized and essential functions in higher eukaryotes associated with antisense promoter and enhancer transcription, and Pol II stability.