Showing papers by "Jin Zhong published in 2006"
TL;DR: The establishment and the characteristics of persistent in vitro infection of human hepatoma-derived cells by a recently described HCV genotype 2a infectious molecular clone reveal the existence of coevolutionary events during persistent HCV infection that favor survival of both virus and host.
Abstract: The virological and cellular consequences of persistent hepatitis C virus (HCV) infection have been elusive due to the absence of the requisite experimental systems. Here, we report the establishment and the characteristics of persistent in vitro infection of human hepatoma-derived cells by a recently described HCV genotype 2a infectious molecular clone. Persistent in vitro infection was characterized by the selection of viral variants that displayed accelerated expansion kinetics, higher peak titers, and increased buoyant densities. Sequencing analysis revealed the selection of a single adaptive mutation in the HCV E2 envelope protein that was largely responsible for the variant phenotype. In parallel, as the virus became more aggressive, cells that were resistant to infection emerged, displaying escape mechanisms operative at the level of viral entry, HCV RNA replication, or both. Collectively, these results reveal the existence of coevolutionary events during persistent HCV infection that favor survival of both virus and host.
251 citations
TL;DR: Overexpression of individual components of the dsRNA-signaling pathway in HCV-infected and uninfected cells indicates that HCV inhibits IFN- beta promoter activity by inactivating the mitochondrial antiviral signaling protein/IFN-beta promoter stimulator 1 (MAVS/IPS-1), while leaving the IFn-induced Janus kinases-signal transducers and activators of transcription signaling pathway intact.
Abstract: The recent establishment of a robust hepatitis C virus (HCV) cell culture system permits analysis of virus-host interactions during HCV infection. Here, we report that HCV genotype 2a (JFH-1) infection fails to induce IFN-β or IFN-stimulated gene expression in Huh-7 cells, and that it blocks IFN-β and IFN-stimulated gene production after transfection of synthetic dsRNA. Overexpression of individual components of the dsRNA-signaling pathway in HCV-infected and uninfected cells indicates that HCV inhibits IFN-β promoter activity by inactivating the mitochondrial antiviral signaling protein/IFN-β promoter stimulator 1 (MAVS/IPS-1), while leaving the IFN-induced Janus kinases-signal transducers and activators of transcription (JAK-STAT) signaling pathway intact. We also show that MAVS/IPS-1-dependent IFN-β promoter activity in HCV-infected cells is fully restored by the nonstructural protein 3 (NS3) protease inhibitor BILN2061. In contrast, synthetic dsRNA-induced IFN-β promoter activity is not restored by BILN2061, although it is partially restored by overexpression of RIG-I. These results support recently reported evidence that the HCV NS3 protease blunts the ability of HCV to induce IFN-β promoter activity by proteolytically cleaving MAVS/IPS-1. The results also suggest that HCV blocks the synthetic dsRNA-induced signaling pathway at a point upstream of MAVS/IPS-1, and that it does so by an NS3-independent mechanism.
120 citations
TL;DR: To disrupt hsa, an essential gene, it is shown that because splicing of the Ll.LtrB intron by the intron-encoded protein is temperature-sensitive, this method yields a conditional hsa disruptant that grows at 32 degrees C but not 43 degrees C.
Abstract: We show that a targetron based on the Lactococcus lactis Ll.LtrB group II intron can be used for efficient chromosomal gene disruption in the human pathogen Staphylococcus aureus. Targetrons expressed from derivatives of vector pCN37, which uses a cadmium-inducible promoter, or pCN39, a derivative of pCN37 with a temperature-sensitive replicon, gave site-specific disruptants of the hsa and seb genes in 37%–100% of plated colonies without selection. To disrupt hsa, an essential gene, we used a group II intron that integrates in the sense orientation relative to target gene transcription and thus could be removed by RNA splicing, enabling the production of functional HSa protein. We show that because splicing of the Ll.LtrB intron by the intron-encoded protein is temperature-sensitive, this method yields a conditional hsa disruptant that grows at 32°C but not 43°C. The temperature sensitivity of the splicing reaction suggests a general means of obtaining one-step conditional disruptions in any organism. In nature, temperature sensitivity of group II intron splicing could limit the temperature range of an organism containing a group II intron inserted in an essential gene.
107 citations
Patent•
09 Aug 2006
TL;DR: In this article, a natto kinase, its coding gene and its application were revealed, in which the natto kase is a protein including one of the sequences of the following amino acid residues, 1), SEQ ID No: 1in the list, 2), the amino acid residue sequence of the SEQ id No:1 in the list is replaced, deleted and added by 1-10 amino acids residues and has fibrinolysis activity
Abstract: This invention discloses a natto kinase, its coding gene and its application, in which, said natto kinase is a protein including one of the sequences of the following amino acid residues, 1), SEQ ID No: 1in the list, 2), the amino acid residue sequence of the SEQ ID No:1 in the list is replaced, deleted and added by 1-10 amino acid residues and has fibrinolysis activity The expression method is to set up a secretory expression carrier of colibacillus with the natto kinase gene to be introduced into a colibacillus to get a re-structured colibacillus to be induced to express the natto kinase gene, which has high fibrinolysis activity
2 citations