Recognition of pTyr1-CTD by the elongation factor Spt6

Pavel Brazda1, Karel Kubicek1, Patrick Cramer2 and Richard Stefl1

1CEITEC – Central European Institute of Technology and Faculty of Science, Masaryk University, CZ-62500 Brno, Czech Republic

2 Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Strasse 25, D-81377 Munich, Germany

The C-terminal domain (CTD) of RNA polymerase II (RNAPII) consists of heptad repeats with the consensus motif Y1-S2-P3-T4-S5-P6-S7. Dynamic post-transcriptional modifications of  the CTD led to the formulation of the so-called “CTD code” more than a decade ago (1). It encodes recruitment of distinct processing factors for each specific position of RNA polymerase II (RNAPII) within the transcriptional cycle (2). However, how the CTD of RNAPII recruits, (de)activates, and displaces relevant processing factors, remains still poorly understood. Recent genome-wide mapping of CTD phosphorylation patterns revealed that Y1 and S2 phosphorylation levels are increased simultaneously during early elongation. Increased Y1 phosphorylation releases factors associated with RNAPII at the beginning of genes, and blocks recruitment of termination factors. In addition, phosphorylated Y1 mark stimulates binding to the tandem SH2 (tSH2) domain of elongation factor Spt6, consistent with Spt6 occupancy within Tyr1-phosphorylated region of genes in vivo (3). We will show our structural data, acquired via a combination of structural methods, supported by biochemical assays on the study of recognition Y1-phosphorylated CTD by the tSH2 domain of the elongation factor Spt6.

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2.         Egloff, S. and Murphy, S.: Cracking the RNA polymerase II CTD code. Trends Genet., 24: 280-8 (2008).

3.         Mayer, A., Heidemann, M., Lidschieber, M., Schreieck, Sun, M., Hintermair, C., Kremmer, E., Eick, D. and Cramer, P.: CTD Tyrosine Phosphorylation Impairs Termination Factor Recruitment to RNA Polymerase II. Science, 336:1723-5 (2012).