Development of a yeast heterologous expression cassette based on the promoter and terminator elements of the translational elongation factor 1α () gene.

A new expression cassette () consisting of the fused 5' and 3' intergenic regions (IGRs) of the translational elongation factor 1α () gene was evaluated through expression of the bacterial hygromycin B phosphotransferase () resistance gene in the common baker's yeast . Progressively shorter versions of the -containing cassette ( though ) with trimmed 5' and 3' IGRs were tested for their ability to confer resistance to hygromycin B in . Hygromycin B resistance was retained in all six generated variants up to a concentration of 400 mg/L. The cassette was the shortest cassette to be assayed in this study with 366 and 155 bp of the 5' and 3' IGRs, respectively. When tested for deletion of the proline oxidase gene , the cassette was shown to successfully act as a selection marker on hygromycin B-containing medium. The cassette could be placed immediately adjacent to a G418 disulfate resistance marker without any discernable effect on the ability of the yeast to grow in the presence of both hygromycin B and G418 disulfate. Co-cultivation experiments under non-selective conditions demonstrated that a deletion strain carrying the cassette displayed equivalent fitness to an otherwise isogenic deletion strain carrying the cassette.