No abstract

A system is described which permits the efficient synthesis of single proteins in vitro. The essential element in this expression system is a strong promoter derived from coliphage T5 which produces, with high efficiency, specific RNAs in capped or uncapped form, depending upon the experimental conditions used. The transcription‐coupled capping of RNA allows the direct translation of the RNA in eukaryotic extracts from wheat germ as well as from HeLa cells. The synthesis of three different proteins is reported, including lysozyme, which is shown to be translocated across membranes when appropriate assay conditions are used. The simplicity of the experimental procedure, the high purity and specific activity of the [35S]methionine‐labelled proteins produced offer a number of possibilities for the study of structure‐function relationships of proteins.

disease (VWD) is a heterogeneous bleeding disorder caused by decrease or dysfunction of von Willebrand factor (VWF). A wide range of mutations in the VWF gene have been characterized; however, their cellular consequences are still poorly understood. Here we have used a recently developed approach to study the molecular and cellular basis of VWD. We isolated blood outgrowth endothelial cells (BOECs) from peripheral blood of 4 type 1 VWD and 4 type 2 VWD patients and 9 healthy controls. We confirmed the endothelial lineage of BOECs, then measured VWF messenger RNA (mRNA) and protein levels (before and after stimulation) and VWF multimers. Decreased mRNA levels were predictive of plasma VWF levels in type 1 VWD, confirming a defect in VWF synthesis. However, BOECs from this group of patients also showed defects in processing, storage, and/or secretion of VWF. Levels of VWF mRNA and protein were normal in BOECs from 3 type 2 VWD patients, supporting the dysfunctional VWF model. However, 1 type 2M patient showed decreased VWF synthesis and storage, indicating a complex cellular defect. These results demonstrate for the first time that isolation of endothelial cells from VWD patients provides novel insight into cellular mechanisms of the disease. (Blood. 2013;121(14):2773-2784