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Viral mRNAs (viral + mrna)
Selected AbstractsTransgenic mice replicating hepatitis B virus but lacking expression of the major HBsAg,JOURNAL OF MEDICAL VIROLOGY, Issue 4 2008Leonie Halverscheid Abstract Hepatitis B Virus (HBV) transgenic mice replicating the viral genome at high level but lacking expression of the small envelope protein (HBsAg) have been produced using a terminally redundant viral DNA construct (HBV 1.4). The generation of viable infectious progeny was dependent on sex and age of mice. Viral mRNA was abundant in liver and kidneys and at low levels in other organs of the mice. No viral particles or HBV envelope proteins could be detected in sera of mice. Despite expression of non-secreted LHBs and MHBs proteins in the liver, there was no accumulation of viral particles in the endoplasmic reticulum of hepatocytes and no necroinflammatory hepatitis was observed. Therefore, these mice represent an excellent model for studies of the role of HBsAg in viral assembly, antiviral immune responses, the further understanding of HBV immunopathogenesis, and the development of antiviral vaccines. J. Med. Virol. 80:583,590, 2008. © 2008 Wiley-Liss, Inc. [source] Inhibition of hepatitis B virus by lentiviral vector delivered antisense RNA and hammerhead ribozymesJOURNAL OF VIRAL HEPATITIS, Issue 4 2005K. L. Nash Summary., Chronic hepatitis B virus (HBV) infection is an important cause of cirrhosis and hepatocellular carcinoma. Current treatments are limited and may be ineffective. Nucleic acid-mediated targeting of viral mRNA is an attractive and specific approach for viral infection and lentiviral vectors provide a means to express antisense sequences or ribozymes stably in target cells permitting continuous production within that cell and its progeny. To demonstrate long-term gene expression by lentiviral vectors in hepatocytes and to introduce lentiviral vectors expressing anti-HBV genes to assess their effect against HBV, lentiviral vectors expressing a reporter gene were assessed for longevity of gene expression in hepatocytes in vitro. Hammerhead ribozymes and antisense sequences targeting the HBV encapsidation signal (,), X or surface antigen on mRNAs were cloned into lentiviral vectors and used to transduce HBV expressing hepatocytes where the effect on HBV mRNA level was assessed using ribonuclease protection. Gene expression in hepatocytes from integrated vectors continued for over 4 months without selection. Antisense RNA targeting HBs mRNA reduced this transcript, whilst antisense RNA to HBX mRNA was ineffective. Sense RNAs corresponding to , and HBX mRNA also reduced HBV mRNA levels. Ribozymes targeting HBs and HBX mRNA effectively reduced HBV mRNA levels compared with inactive constructs indicating their effect to be enzymatic rather than antisense. Lentiviral vectors can produce long-term gene expression in hepatocytes and thus permit prolonged expression of antiviral genes targeting the HBV encapsidation signal, surface and X mRNAs as treatments for chronic HBV infection. [source] Rev response elements (RRE) in lentiviruses: An RNAMotif algorithm-based strategy for RRE predictionMEDICINAL RESEARCH REVIEWS, Issue 6 2002Elena A. Lesnik Abstract Lentiviruses (a sub-family of the retroviridae family) include primate and non-primate viruses associated with chronic diseases of the immune system and the central nervous system. All lentiviruses encode a regulatory protein Rev that is essential for post-transcriptional transport of the unspliced and incompletely spliced viral mRNAs from nuclei to cytoplasm. The Rev protein acts via binding to an RNA structural element known as the Rev responsive element (RRE). The RRE location and structure and the mechanism of the Rev-RRE interaction in primate and non-primate lentiviruses have been analyzed and compared. Based on structural data available for RRE of HIV-1, a two step computational strategy for prediction of putative RRE regions in lentivirus genomes has been developed. First, the RNAMotif algorithm was used to search genomic sequence for highly structured regions (HSR). Then the program RNAstructure, version 3.6 was used to calculate the structure and thermodynamic stability of the region of , 350 nucleotides encompassing the HSR. Our strategy correctly predicted the locations of all previously reported lentivirus RREs. We were able also to predict the locations and structures of potential RREs in four additional lentiviruses. © 2002 Wiley Periodicals, Inc. Med Res Rev, 22, No. 6, 617,636, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/med.10027 [source] Resistance to cassava mosaic disease in transgenic cassava expressing antisense RNAs targeting virus replication genesPLANT BIOTECHNOLOGY JOURNAL, Issue 4 2005Peng Zhang Summary African cassava mosaic virus (ACMV) is a major contributor to cassava mosaic disease (CMD), the economically most important and devastating disease of cassava in Africa. We have developed transgenic cassava plants with increased ACMV resistance using improved antisense RNA technology by targeting the viral mRNAs of Rep (AC1), TrAP (AC2) and REn (AC3). Viral DNA replication assays in detached leaves demonstrated that replication of two ACMV isolates was strongly reduced or inhibited in most transgenic lines. After ACMV infection of plants using biolistic inoculation, several lines remained symptomless at lower infection pressure (100 ng viral DNA/plant). Symptom development was reduced and attenuated even at higher DNA doses. Transgenic ACMV-resistant plants had significantly reduced viral DNA accumulation in their infected leaves. Short sense and antisense RNAs specific to AC1 were identified in transgenic lines expressing AC1 antisense RNA, suggesting that the short RNAs mediate interference by post-transcriptional gene silencing. Our results demonstrate that resistance to ACMV infection of cassava can be achieved with high efficacy by expressing antisense RNAs against viral mRNAs encoding essential non-structural proteins, providing a new tool to combat CMD in Africa. [source] | ||||||||||