TY - JOUR
T1 - Molecular Basis of Transcription-Coupled Pre-mRNA Capping
AU - Martinez-Rucobo, Fuensanta W.
AU - Kohler, Rebecca
AU - van de Waterbeemd, Michiel
AU - Heck, Albert J R
AU - Hemann, Matthias
AU - Herzog, Franz
AU - Stark, Holger
AU - Cramer, Patrick
PY - 2015/6/18
Y1 - 2015/6/18
N2 - Capping is the first step in pre-mRNA processing, and the resulting 5'-RNA cap is required for mRNA splicing, export, translation, and stability. Capping is functionally coupled to transcription by RNA polymerase (Pol) II, but the coupling mechanism remains unclear. We show that efficient binding of the capping enzyme (CE) to transcribing, phosphorylated yeast Pol II (Pol IIp) requires nascent RNA with an unprocessed 5'-triphosphate end. The transcribing Pol IIp-CE complex catalyzes the first two steps of capping, and its analysis by mass spectrometry, cryo-electron microscopy, and protein crosslinking revealed the molecular basis for transcription-coupled pre-mRNA capping. CE docks to the Pol II wall and spans the end of the RNA exit tunnel to position the CE active sites for sequential binding of the exiting RNA 5' end. Thus, the RNA 5' end triggers its own capping when it emerges from Pol II, to ensure seamless RNA protection from 5'-exonucleases during early transcription.
AB - Capping is the first step in pre-mRNA processing, and the resulting 5'-RNA cap is required for mRNA splicing, export, translation, and stability. Capping is functionally coupled to transcription by RNA polymerase (Pol) II, but the coupling mechanism remains unclear. We show that efficient binding of the capping enzyme (CE) to transcribing, phosphorylated yeast Pol II (Pol IIp) requires nascent RNA with an unprocessed 5'-triphosphate end. The transcribing Pol IIp-CE complex catalyzes the first two steps of capping, and its analysis by mass spectrometry, cryo-electron microscopy, and protein crosslinking revealed the molecular basis for transcription-coupled pre-mRNA capping. CE docks to the Pol II wall and spans the end of the RNA exit tunnel to position the CE active sites for sequential binding of the exiting RNA 5' end. Thus, the RNA 5' end triggers its own capping when it emerges from Pol II, to ensure seamless RNA protection from 5'-exonucleases during early transcription.
UR - http://www.scopus.com/inward/record.url?scp=84937641334&partnerID=8YFLogxK
U2 - 10.1016/j.molcel.2015.04.004
DO - 10.1016/j.molcel.2015.04.004
M3 - Article
C2 - 25959396
AN - SCOPUS:84937641334
SN - 1097-2765
VL - 58
SP - 1079
EP - 1089
JO - Molecular Cell
JF - Molecular Cell
IS - 6
ER -