Biotechnology Letters, Vol.29, No.8, 1233-1241, 2007
Heterologous expression of cyan and yellow fluorescent proteins from the Kluyveromyces lactis KlMAL21-KlMAL22 bi-directional promoter
We have identified the Kluyveromyces lactis maltase (KlMAL22) and maltose permease (KlMAL21) intergenic region as a candidate bidirectional promoter for heterologous gene expression. The expressions of cyan and yellow fluorescent proteins from, respectively, the KlMAL22 and KlMAL21 orientations of the promoter, were compared between two promoter variants during growth in media containing glucose, galactose or glycerol. Expression from both orientations of the native promoter was repressed during growth in glucose and galactose and was induced during growth in glycerol. Disruption of a putative Mig1p binding site caused some de-repression of the maltase orientation of the promoter by 48 h of growth in glucose. The KlMAL21-KlMAL22 bi-directional promoter can be used to carry out regulated expression of heterologous gene products.
Keywords:bi-directional promoter;cyan fluorescent protein;glucose repression;heterologous protein expression;Kluyveromyces lactis;maltase;maltose permease;yellow fluorescent protein