Effects of splitting alternative KlCYC1 3′-UTR regions on processing: Metabolic consequences and biotechnological applications

To analyze the functionality of alternative 3′-UTR processing in the yeast Kluyveromyces lactis, recombinant forms of the KlCYC1 gene containing the proximal (1-713) or the distal (699-1194) 3′-UTR region (positions related to the TAA stop codon) were obtained. The cells expressing the gene with proximal 3′-UTR showed the same growth phenotype as the wild type. When the gene expressed only the distal region, a single transcript was generated and its expression was increased in late-growth phases. Cells expressing the alternative distal 3′-UTR region showed differences in their levels of cytochrome c biomass and ethanol production with respect to the wild type. The split 3′-UTR regions were also functional as separate processing units in Saccharomyces cerevisiae. The importance of our results in recombinant gene expression applications will be discussed.