The Firefly-Luciferase (F-Luc) mRNA expresses firefly luciferase protein, which is the enzyme for bioluminescence of fireflies and click beetles. After efficient delivery into cells or animals, F-Luc mRNA can translate into F-Luc and emit bioluminescence in the presence of its substrate, Luciferin. This mRNA is capped with Cap1 structure with high capping efficiency. It has 100% substituted with N1-methyl-pseudo Uridine for enhanced expression and reduced immunogenicity. The mRNA has a 100A tail in its sequence, mimics a mature mRNA.