EPO-mRNA is an mRNA molecule capped at the 5' end, polyadenylated at the 3' end, and modified with N1-Me-Pseudo UTP, mimicking the processed mature mRNA found in eukaryotes. The mRNA is capped co-transcriptionally using 3'-O-Me-GAG, forming a Cap1 structure which enhances mRNA stability and translation efficiency. The incorporation of the modified nucleotide N1-Me-Pseudo UTP reduces innate immune stimulation and increases mRNA stability. The addition of the poly(A) tail further stabilizes the mRNA and enhances its translation initiation efficiency.