PMID: 26060179
Male G, von Appen A, Glatt S, Taylor NM, Cristovao M, Groetsch H, Beck M, Muller CW
Architecture of TFIIIC and its role in RNA polymerase III pre-initiation complex assembly.
Nat Commun. 2015 Jun 10;6:7387. doi: 10.1038/ncomms8387.
In eukaryotes, RNA Polymerase III (Pol III) is specifically responsible for transcribing genes encoding tRNAs and other short non-coding RNAs. The recruitment of Pol III to tRNA-encoding genes requires the transcription factors (TF) IIIB and IIIC. TFIIIC has been described as a conserved, multi-subunit protein complex composed of two subcomplexes, called tauA and tauB. How these two subcomplexes are linked and how their interaction affects the formation of the Pol III pre-initiation complex (PIC) is poorly understood. Here we use chemical crosslinking mass spectrometry and determine the molecular architecture of TFIIIC. We further report the crystal structure of the essential TPR array from tauA subunit tau131 and characterize its interaction with a central region of tauB subunit tau138. The identified tau131-tau138 interacting region is essential in vivo and overlaps with TFIIIB-binding sites, revealing a crucial interaction platform for the regulation of tRNA transcription initiation.