In Escherichia coli, the CpxR/A two-component system senses various types of extracytoplasmic stresses and responds by activating the expression of genes encoding periplasmic protein folding and trafficking factors that clear such stresses to ensure the organism's survival. The cpxP gene encodes a small, stress-combative periplasmic protein and is the most strongly induced member of the Cpx reg...

We have developed a bacterial system for the discovery of interacting proteins that, unlike other two-hybrid technologies, allows for the selection of protein pairs on the basis of affinity or expression. This technology relies on the anchored periplasmic expression (APEx) of one protein (bait) on the periplasmic side of the inner membrane of Escherichia coli and its interacting partner (prey) ...

We have been using the human multiple drug resistance (MDR) gene to transduce murine hematopoietic cells via retroviruses as a model system for potential human gene therapy. In this paper, we show that transplantation of MDR-transduced midgestational fetal liver cells (FLCs) into lethally irradiated mice leads to the continued presence and expression of the human MDR gene in the short-lived gra...

A novel strategy to increase protein expression yield is unintended induction of expression in complex media, called auto-induction. This method can be used to express proteins under control of the lac promoter without any need to monitor bacterial growth pattern, and addition of specific expression inducers such as Isopropyl β-D-1-thiogalactopyranoside (IPTG) at proper time. In the present stu...

DegS, the periplasmic stress sensor, becomes activated when its PDZ domain recognizes the improperly exposed C-terminal sequences of outer membrane porins. This interaction relieves the inhibition of the neighboring protease domain of DegS, triggering a proteolysis cascade that leads to the sigma(E)-driven expression of periplasmic chaperones.