Structural details of the interaction between pTyr1-CTD and the elongation factor Spt6

Pavel Brázda1, Magdaléna Krejčíková1, Eliška Šmiřáková, Jiří Nováček1, Karel Kubíček1, Patrick Cramer2 and Richard Štefl1

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

Post-transcriptional modifications of the consensus motif Y1-S2-P3-T4-S5-P6-S7 of the C-terminal domain (CTD) of RNA polymerase II (RNAPII) are since last decade known as “CTD code” (1). These modifications are dynamic and specific for each phase of the transcriptional cycle (2). However, how does the CTD code control the recruitment, (de)activation, and displacement of relevant processing factors, remains still poorly understood. Increased phosphorylation level of Y1 of the CTD during the early elongation inhibits binding of termination factors, yet it stimulates binding of the elongation factor Spt6 through its tandem SH2 (tSH2) domain (3). The limited structure information for the recognition of phospho-tyrosine modified CTD that is currently available prevents deciphering of how this important CTD modification mark is read out by transcription factors (4,5). We set out to investigate this recognition phenomenon using integrative approach to structural biology. Here, we will show our combined structural data from NMR, X-ray, and SAXS along with binding and biochemical assays on the study of recognition Y1-phosphorylated CTD by the tSH2 domain of the elongation factor Spt6.

1.         Buratowski, S.:, The CTD code. Nat Struct Biol., 10:679-80 (2003).

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

3.         Mayer, A., Heidemann, M., Lidschreiber, 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).

4.         Sun, M., Lariviere, L., Dengl, S., Mayer, A., Cramer, P., A tandem SH2 domain in transcription elongation factor Spt6 binds the phosphorylated RNA polymerase II C-terminal repeat domain (CTD), J.Biol.Chem. 285: 41597-41603 (2010).

5.         Diebold, M., Loeliger, E., Koch, M., Winston, F., Cavarelli, J., Romier, C., Noncanonical Tandem Sh2 Enables Interaction of Elongation Factor Spt6 with RNA Polymerase II, J.Biol.Chem. 285: 38389 (2010).