microRNA-122 stimulates translation of hepatitis C virus RNA

Hepatitis C virus (HCV) is a positive strand RNA virus that propagates primarily in the liver. We show here that the liver-specific microRNA-122 (miR-122), a member of a class of small cellular RNAs that mediate post-transcriptional gene regulation usually by repressing the translation of mRNAs through interaction with their 3′-untranslated regions (UTRs), stimulates the translation of HCV. Sequestration of miR-122 in liver cell lines strongly reduces HCV translation, whereas addition of miR-122 stimulates HCV translation in liver cell lines as well as in the non-liver HeLa cells and in rabbit reticulocyte lysate. The stimulation is conferred by direct interaction of miR-122 with two target sites in the 5′-UTR of the HCV genome. With a replication-defective NS5B polymerase mutant genome, we show that the translation stimulation is independent of viral RNA synthesis. miR-122 stimulates HCV translation by enhancing the association of ribosomes with the viral RNA at an early initiation stage. In conclusion, the liver-specific miR-122 may contribute to HCV liver tropism at the level of translation

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

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 1997–2012, 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

Electronic structure and thermodynamic properties of Ce3Rh4Sn13 and La3Rh4Sn13

We report on the electronic structure and basic thermodynamic properties of Ce3Rh4Sn13 and of the reference compound La3Rh4Sn13. XPS core-level spectra revealed a stable trivalent configuration of the Ce atoms in Ce3Rh4Sn13, consistent with magnetic susceptibility data. Band structure calculations within the LSDA+U approximation yield the qualitatively correct description of Ce in a trivalent state. The reliability of the theoretical results has been confirmed by a comparison of the calculated XPS valence band spectra with experimental data. The calculated densities of states as well as the rare-earth (RE) 3d XPS spectra point to a weak hybridization between the RE 4f shell and the conduction band states. The band structure calculations result in a magnetic ground state for Ce3Rh4Sn13. Previous analysis pointed to the partial occupancy of the 2a site by Sn atoms. The charge density analysis reveals the dominant metallic character of the chemical bonding at the 2a atomic position. Simulation of vacancies at the 2a site using the virtual crystal approximation (VCA) indicate that the magnetic properties of Ce3Rh4Sn13 strongly depend on the Sn content, which could explain the discrepancy in magnetic properties between different Ce3Rh4Sn13 samples