Whole-genome combinatorial gene fusions generate novel genes for advanced microbial trait development

In biotechnology, gene fusion is a valuable molecular evolution tool for tagging proteins of interest and for combining or altering protein activities. To broadly demonstrate and harness the gain-of-function capabilities of fusion genes in a whole-genome approach, we constructed a “Function Generator™” fusion gene library containing pairwise combinations of 5019 protein-coding sequences in the Saccharomyces cerevisiae genome.

The open reading frames (ORFs) were PCR amplified from the S288C yeast genome and cloned into a centromeric expression vector, with each ORF represented in the 5’ and the 3’ positions of the resulting gene fusions. To illustrate the ability of fusion genes in the library to confer complex phenotypes, a population of yeast library transformants was screened for resistance to four toxic heavy metal ions (Cd+2, Co+2, Cu+2 and Ni+2).