Negative control glucose dependent mediated by the PreS 2 region on the translation efficiency of the reporter Sh-bleomycin gene in Saccharomyces cerevisiae.

Saccharomyces cerevisiae is able to sense and respond to environmental changes such as the availability of carbon sources. In a previous work, we showed that the expression of the Pre S2- S gene of HBV in yeast was negatively regulated at the translational level dependent of glucose. In this study, we show that the S m RNA is detected in the polysomes indicating its active translation, while the Pre S2- S m RNA was mainly found in monosomes. Moreover, we used the gene reporter assay based on Zeocin resistance, to better characterize the Pre S2 region responsible for this control. Two chimeric genes composed of the N- and C-terminal part of the Pre S2 fused to the Sh-bleomycin gene conferring the resistance to Zeocin were expressed in yeast. We found that the strain expressing the N-terminal part of the Pre S2 was sensitive to Zeocin on rich medium with 2% glucose. In contrast, the strain harbouring the C-terminal part of the Pre S2 fused to the Sh-bleomycin grew on Zeocin, indicating that the Sh-bleomycin m RNA is efficiently translated, subsequently conferring resistance to Zeocin. Our data suggest the establishment of a translational control via the N-terminal part of the Pre S2 mediated by the presence of 2% glucose in the media. [ABSTRACT FROM AUTHOR]