87 research outputs found
Serine Phosphoacceptor Sites within the Core Protein of Hepatitis B Virus Contribute to Genome Replication Pleiotropically
The core protein of hepatitis B virus can be phosphorylated at serines 155, 162, and 170. The contribution of these serine residues to DNA synthesis was investigated. Core protein mutants were generated in which each serine was replaced with either alanine or aspartate. Aspartates can mimic constitutively phosphorylated serines while alanines can mimic constitutively dephosphorylated serines. The ability of these mutants to carry out each step of DNA synthesis was determined. Alanine substitutions decreased the efficiency of minus-strand DNA elongation, primer translocation, circularization, and plus-strand DNA elongation. Aspartate substitutions also reduced the efficiency of these steps, but the magnitude of the reduction was less. Our findings suggest that phosphorylated serines are required for multiple steps during DNA synthesis. It has been proposed that generation of mature DNA requires serine dephosphorylation. Our results suggest that completion of rcDNA synthesis requires phosphorylated serines
Tandem fusion of hepatitis B core antigen allows assembly of virus-like particles in bacteria and plants with enhanced capacity to accommodate foreign proteins
The core protein of the hepatitis B virus, HBcAg, assembles into highly immunogenic viruslike particles (HBc VLPs) when expressed in a variety of heterologous systems. Specifically, the major insertion region (MIR) on the HBcAg protein allows the insertion of foreign sequences, which are then exposed on the tips of surface spike structures on the outside of the assembled particle. Here, we present a novel strategy which aids the display of whole proteins on the surface of HBc particles. This strategy, named tandem core, is based on the production of the HBcAg dimer as a single polypeptide chain by tandem fusion of two HBcAg open reading frames. This allows the insertion of large heterologous sequences in only one of the two MIRs in each spike, without compromising VLP formation. We present the use of tandem core technology in both plant and bacterial expression systems. The results show that tandem core particles can be produced with unmodified MIRs, or with one MIR in each tandem dimer modified to contain the entire sequence of GFP or of a camelid nanobody. Both inserted proteins are correctly folded and the nanobody fused to the surface of the tandem core particle (which we name tandibody) retains the ability to bind to its cognate antigen. This technology paves the way for the display of natively folded proteins on the surface of HBc particles either through direct fusion or through non-covalent attachment via a nanobody
Foreign ownership, bank information environments, and the international mobility of corporate governance
This paper investigates how foreign ownership shapes bank information environments. Using a sample of listed banks from 60 countries over 1997â2012, we show that foreign ownership is significantly associated with greater (lower) informativeness (synchronicity) in bank stock prices. We also find that stock returns of foreign-owned banks reflect more information about future earnings. In addition, the positive association between price informativeness and foreign ownership is stronger for foreign-owned banks in countries with stronger governance, stronger banking supervision, and lower monitoring costs. Overall, our evidence suggests that foreign ownership reduces bank opacity by exporting governance, yielding important implications for regulators and governments
Banking across borders with heterogeneous banks
This code repository contains Matlab codes to reproduce the simulations discussed in sections 4.2 (Model simulation) and 4.3 (Insights for financial sector policies) and appendix B (General model with tau=phi=1)
Banking across borders with heterogeneous banks
This code repository contains Matlab codes to reproduce the simulations discussed in sections 4.2 (Model simulation) and 4.3 (Insights for financial sector policies) and appendix B (General model with tau=phi=1).THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
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