Expression of recombinant human tropoelastin in Saccharomyces cerevisiae containing a synthetic gene with a high codon adaptation index coupled to the SUC2 invertase signal sequence

Tropoelastin is the soluble precursor of vertebrate elastin. but the gene i s absent in lower eukaryotes, which are not organized into complex multicel lular arrays. A synthetic gene encoding human tropoelastin with a high codo n adaptation index was examined for expression in Saccharomyces cerevisiae. The expression of tropoelastin transcript increased similar to 20-fold fol lowing induction. The native cytoplasm-expressed form of tropoelastin was n ot detected. In contrast, N-terminal fusion of the SUC2 invertase signal se quence of the yeast to tropoelastin led to the production of intracellular full-length protein and enhanced its stability in vivo. There was no eviden ce of extracellular secretion of the protein. We conclude that eukaryotic c ells are capable of expressing and retaining undegraded tropoelastin in the absence of a vertebrate-specific protein partner. Tropoelastin was directe d to the yeast endoplasmic reticulum through the interim presence of the SU C2 signal peptide sequence.