Studies performed in Winfried Boos' laboratory at the University of Konstanz, expanded the classic Jacob & Monod model of gene regulation in which an external inducer is taken up by cells to interact with a transcription factor. We have shown by using the maltose regulon as a model that specific endogenous i.e. intracellular inducers function as regulators of gene expression. These endogenous inducers can, under certain conditions, have larger effects than exogenous inducers.

In Jon Beckwith's laboratory at Harvard Medical School the gene fusion technology was expanded by generating the first sandwich fusions of membrane proteins and alkaline phosphatase for topological studies. In addition, genetic studies performed in collaboration with Dana Boyd and Karen McGovern revealed the determinants of membrane protein topology. Another aspect of our past research was the design of the "Targeted Directed Proteolysis in vivo" (TDP) approach. TDP uses the specific Tobacco Etch Virus NIa (TEV) protease. Polypeptides that are not natural substrates are proteolysed if they carry an engineered cleavage site. This method was applied to conditionally inactivate essential proteins and to study their structure, function and translocation in living cells. We have also shown that TEV protease can be even attached to the exit tunnel of the ribosome where it cleaves nascent chains of target substrates. We were the first to show that non-natural biochemical activities can be recruited to the ribosome.