Abstract: A method is disclosed for determining the translational efficiency of an individual codon in a cell. The method comprises introducing into the cell a synthetic construct comprising a reporter polynucleotide fused in frame with a tandem repeat of said individual codon, wherein said reporter polynucleotide encodes a reporter protein, and wherein said synthetic construct is operably linked to a regulatory polynucleotide and measuring expression of said reporter protein in said cell to determine the translational efficiency of said codon.

Abstract: A synthetic polynucleotide and a method are disclosed for selectively expressing a protein in a target cell or tissue of a mammal. Selective expression is effected by replacing at least one existing codon of a parent polynucleotide encoding a protein of interest with a synonymous codon to produce a synthetic polynucleotide having altered translational kinetics compared to the parent polynucleotide. The synonymous codon is selected such that it has a higher translational efficiency in the target cell or tissue relative to one or more other cells or tissues of the mammal.

Abstract: A method is disclosed for constructing a synthetic polynucleotide from which a protein is selectively expressible in a target cell of a plant, relative to another cell of the plant. The method comprises selecting a first codon of a parent polynucleotide for replacement with a synonymous codon which has a higher translational efficiency in the target cell than in said other cell, and replacing said first codon with said synonymous codon to form said synthetic polynucleotide.