HR-Bac, a toolbox based on homologous recombination for expression, screening and production of multiprotein complexes using the baculovirus expression system

International audienceAbstract The Baculovirus/insect cell expression system is a powerful technology for reconstitution of eukaryotic macromolecular assemblies. Most multigene expression platforms rely on Tn7-mediated transposition for transferring the expression cassette into the baculoviral genome. This allows a rigorous characterization of recombinant bacmids but involves multiple steps, a limitation when many constructs are to be tested. For parallel expression screening and potential high throughput applications, we have established an open source multigene-expression toolbox exploiting homologous recombination, thus reducing the recombinant baculovirus generation to a single-step procedure and shortening the time from cloning to protein production to 2 weeks. The HR-bac toolbox is composed of a set of engineered bacmids expressing a fluorescent marker to monitor virus propagation and a library of transfer vectors. They contain single or dual expression cassettes bearing different affinity tags and their design facilitates the mix and match utilization of expression units from Multibac constructs. The overall cost of virus generation with HR-bac toolbox is relatively low as the preparation of linearized baculoviral DNA only requires standard reagents. Various multiprotein assemblies (nuclear hormone receptor heterodimers, the P-TEFb or the ternary CAK kinase complex associated with the XPD TFIIH subunit) are used as model systems to validate the toolbox presented

Active mRNA degradation by EXD2 nuclease elicits recovery of transcription after genotoxic stress

Here the authors show that the exonuclease EXD2 is involved in the recovery of class II gene transcription after UV irradiation. EXD2 travels from the mitochondria to the nucleus to interact with RNA Pol II and degrade new synthetized mRNA to allow transcription following DNA repair