STOICHIOMETRIC EXPRESSION OF MESSENGER POLYCISTRONS

Disclosed herein include methods, compositions, and kits enabling expression of multiple proteins from a single mRNA with a predetermined stoichiometry. There are provided, in some embodiments, nucleic acid compositions comprising a promoter operably linked to a polynucleotide comprising a first nucleic acid unit encoding first unit payload protein(s) and a second nucleic acid unit encoding second unit payload protein(s). The first nucleic acid unit and the second nucleic acid unit can each comprise a 3′ engineered translation initiation site (eTIS) comprising a three-nucleotide tunable element immediately upstream of a start codon. The eTIS of each of the first nucleic acid unit and the second nucleic acid unit can be configured to achieve a predetermined stoichiometry of the first unit payload protein(s) and the second unit payload protein(s) in a cell or cell-like environment.