Molecular analysis of a synthetic tetracycline-binding riboswitch.

Riboswitches are newly discovered regulatory elements that consist solely of RNA, sense their ligand in a preformed binding pocket, and perform a conformational switch in response to ligand binding, resulting in altered gene expression. Regulation by a tetracycline (tc)-binding aptamer when inserted into the 5' untranslated region (UTR) of a reporter gene exhibits all characteristics of a riboswitch. Chemical and enzymatic probing reveals that the aptamer consists of two stems, P1 and P2, which are already present in the absence of tc and form the scaffold of the aptamer.

Tetracycline-aptamer-mediated translational regulation in yeast.

We describe post-transcriptional gene regulation in yeast based on direct RNA-ligand interaction. Tetracycline-dependent translational regulation could be imposed via specific aptamers inserted at two different positions in the 5' untranslated region (5'UTR). Translation in vivo was suppressed up to ninefold upon addition of tetracycline.

Conditional gene expression by controlling translation with tetracycline-binding aptamers.

We present a conditional gene expression system in Saccharomyces cerevisiae which exploits direct RNA-metabolite interactions as a mechanism of genetic control. We inserted preselected tetracycline (tc) binding aptamers into the 5'-UTR of a GFP encoding mRNA. While aptamer insertion generally reduces GFP expression, one group of aptamers displayed an additional, up to 6-fold, decrease in fluorescence upon tc addition.