In molecular biology, the five-prime cap (5′ cap) is a specially altered nucleotide on the 5′ end of some primary transcripts such as precursor messenger RNA. This process, known as mRNA capping, is highly regulated and vital in the creation of stable and mature messenger RNA able to undergo translation during protein synthesis.

In this review, we will summarize the current knowledge of the biological roles of mRNA caps in eukaryotic cells. We will also discuss different means that viruses and their host cells use to cap their RNA and the application of these capping machineries to synthesize functional mRNA.

The absence of capped RNA is considered as a hallmark of prokaryotic gene expression. Recent developments combine next-generation sequencing with a chemo-enzymatic capture step that allows the enrichment of rare 5′-modified RNA from bacteria.

Recent studies have uncovered an RNA 5′ capping quality surveillance mechanism, with DXO/Rai1 decapping enzymes removing incomplete caps and enabling the degradation of the RNAs, in a process we also refer to as “no-cap decay.”

The mRNA cap is a highly methylated modification of the 5′ end of RNA pol II-transcribed RNA. It protects RNA from degradation, recruits complexes involved in RNA processing, export and translation initiation, and marks cellular mRNA as “self” to …

Jan 18, 2024 · The critical redox cofactor NAD+ was recently reported to serve as an RNA cap in both eukaryotes and prokaryotes. However, its reversible regulation and biological functions remain unclear.

Apr 9, 2025 · Explore IVT mRNA capping methods and learn about different cap structures to enhance mRNA stability, translation, and therapeutic efficacy.

Jul 7, 2016 · We report crystal structures of transcription initiation complexes containing NCIN-capped RNA products. Our results define the mechanism and structural basis of NCIN capping, and suggest that NCIN-mediated “ ab initio capping” may occur in all organisms.

Capping is the first step in the maturation of eukaryotic mRNA. Shortly after the start of transcription, the 5′-end of the growing RNA molecule is capped by the addition of a guanosine monophosphate residue (from GTP) via a 5′-5′ pyrophosphate linkage.

To increase the availability of capped mRNA analogs, we present here a practical and non-templated approach based on the use of click ligation resulting in RNAs bearing a single triazole linkage within the oligo-phosphate backbone.