KLUYVEROMYCES-LACTIS KILLER SYSTEM - ANALYSIS OF CYTOPLASMIC PROMOTERS OF THE LINEAR PLASMIDS

Ail of the 14 genes encoded by the cytoplasmic linear killer plasmids of Kluyveromyces lactis are preceded by upstream conserved sequences ( UCSs), cis-acting elements involved in plasmid gene transcription, Usi ng the bacterial glucose-dehydrogenase gene as a reporter, expression driven by seven cytoplasmic promoters was determined. The level of exp ression ranged from 0.5 to 6 nkat, The highest activity was displayed by UCS 6 of pGKL2 whereas the lowest level was obtained with UCS2 of p GKL2, all other values were in between, Sequences located 5' upstream the UCSs do not influence expression, As exemplified for UCS5 and UCS1 0, deletion led to an almost complete loss of expression.