Kluyveromyces lactis killer system: Identification of a new gene encoded by pGKL2

The cytoplasmic linear plasmid pGKL2 of the yeast Kluyveromyces lactis was reported to harbour ten open reading frames (ORF1-ORF10). By re-examining t he sequence, we identified an additional ORF encoding a polypeptide of 70 a mino acids; and a homologous ORF with 70% similarity was also identified on plasmid pSKL of Saccharomyces kluyveri. As for pGKL2, the newly detected O RF11 is located at the same position with the same direction. ORF11 transcr ipts of pGKL2 were verified by reverse transcriptase-polymerase chain react ion; and the corresponding promoter activity was proven by expression of a reporter gene driven by the ORF11 upstream conserved sequence, indicating t hat ORF11 constitutes a functional gene.