Abstract: Disclosed is a nucleic acid comprising a nucleotide sequence encoding (i) two or more reporters comprising a first reporter and a second reporter that is different from the first reporter; and (ii) one or more ribosomal skip sequences, wherein a ribosomal skip sequence is positioned between the first and second reporters, wherein the first and second reporters are stoichiometrically co-expressed from the nucleotide sequence and the nucleic acid does not comprise a cytomegalovirus-immediate early (CMV-IE) promoter. Also disclosed are methods of screening test compounds for ability to modulate a biological activity of interest using the nucleic acid, as well as related recombinant expression vectors, host cells, and populations of cells.