期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2020
卷号：117
期号：9
页码：4445-4446
DOI：10.1073/pnas.2000341117
出版社：The National Academy of Sciences of the United States of America
摘要：RNA capping in eukaryotes has been studied since the 1970s, starting with the discovery of 5′ 7-methylguanylate caps in the Shatkin laboratory (1). That capping mechanism involves a pause during transcription elongation that allows the recruitment of specialized capping enzymes to modify the 5′ end of the nascent RNA. In bacteria, however, RNA capping was observed only within the past decade when derivatives of either coenzyme A (CoA) (2) or nicotinamide adenine dinucleotide (NAD) (3, 4) were reported at some RNA 5′ ends. The first bacterial capping mechanism was established convincingly in 2016 when it was observed that RNA polymerase (RNAP) could incorporate caps into RNA by using NAD and CoA as noncanonical initiating nucleotides (5). Last year, the Belasco laboratory at New York University demonstrated that a different type of cap, namely nucleoside tetraphosphate (Np4), is found at the 5′ end of RNAs in Escherichia coli (6) under conditions where dinucleoside tetraphosphates (Np4N) are increased. In PNAS, Luciano and Belasco (7) demonstrate the ability of E. coli RNAP to use Np4N as the initiating nucleotide and its dependence on promoter sequence. In some cases, incorporation of an Np4N is strongly favored over initiation … [↵][1]1To whom correspondence may be addressed.
