Cap-0 is a N7-methyl guanosine connected to the 5′ nucleotide through a 5′ to 5′ triphosphate linkage, typically refers to as m7G cap or m7Gppp- in the literature. In the cell, the Cap-0 structure is essential for efficient translation of the mRNA that carries the cap. An additional methylation on the 2′O position of the initiating nucleotide generates Cap-1, or refers to as m7GpppNm-, where Nm denotes any nucleotide with a 2′O methylation. Cap-1 has been shown to be important in evading the cellular innate immune response in vivo.