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Updated: Aug 17, 2026

In vitro Transcription and Capping of Gaussia Luciferase mRNA Followed by HeLa Cell Transfection
Published on: March 26, 2012
5'-Capping enzymes are targeted to pre-mRNA by binding to the phosphorylated carboxy-terminal domain of RNA
S McCracken1, N Fong, E Rosonina
1Amgen Institute and Ontario Cancer Institute, Toronto, Ontario M5G 2C1, Canada.
Abstract:
We have investigated the role of the RNA Polymerase II (Pol II) carboxy-terminal domain (CTD) in mRNA 5' capping. Transcripts made in vivo by Pol II with a truncated CTD had a lower proportion of capped 5' ends than those made by Pol II with a full-length CTD. In addition, the enzymes responsible for cap synthesis, RNA guanylyltransferase, and RNA (guanine-7)-methyltransferase bound directly to the phosphorylated, but not to the nonphosphorylated, form of the CTD in vitro. These results suggest that: (1) Pol II-specific capping of nascent transcripts in vivo is enhanced by recruitment of the capping enzymes to the CTD and (2) capping is co-ordinated with CTD phosphorylation.
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