Expression of Recombinant Human Tropoelastin inSaccharomyces cerevisiae Containing a Synthetic Gene with a High Codon Adaptation Index Coupled to theSUC2 Invertase Signal Sequence

Abstract

Tropoelastin is the soluble precursor of vertebrate elastin,but the gene is absent in lower eukaryotes, which are not organized into complex multicellular arrays. A synthetic gene encoding human tropoelastin with a high codon adaptation index was examined for expression in Saccharomyces cerevisiae. The expression of tropoelastin transcript increased. ∼20-fold following induction. The native cytoplasm-expressed form of tropoelastin was not detected. In contrast, N-terminal fusion of the SUC2 invertase signal sequence of the yeast to tropoelastin led to the production of intracellular full-length protein and enhanced its stability in vivo. There was no evidence of extracellular secretion of the protein.We conclude that eukaryotic cells are capable of expressing and retaining undegraded tropoelastin in the absence of a vertebrate-specific protein partner. Tropoelastin was directed to the yeast endoplasmic reticulum through the interim presence of the SUC2 signal peptide sequence.