5-Methyl-CTP is a modified nucleoside triphosphate, commonly used to substitute the naturally occurring cytidine triphosphate (CTP) during in vitro mRNA synthesis. Methylation of the cytosine C-5 position is a common, post-transcriptional modification for mRNA. Incorporation of chemically modified 5-methyl-CTP can increase mRNA stability and protein expression, and meanwhile, reduce interaction of innate immune receptors with in vitro-transcribed (IVT) mRNA. Apart from its application in encoding antigens for the activation of immune response against a variety of diseases such as COVID-19, IVT mRNA can also express the nanobody/variable domain of heavy chain of heavy-chain antibody targeting the intracellular components, enabling intracellular antigen labeling and manipulation.
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