Temporal modulation of an autoprotease is crucial for replication and pathogenicity of an RNA virus.
ABSTRACT Pestiviruses belong to the family Flaviviridae, and their genome is a single-stranded RNA of positive polarity encoding one large polyprotein which is further processed into mature proteins. Noncytopathogenic (noncp) strains of the pestivirus bovine viral diarrhea virus (BVDV) can establish persistent infection. In persistently infected animals, noncp BVDVs occasionally acquire mutations in viral nonstructural protein 2 (NS2) that give rise to cytopathogenic (cp) BVDV variants, and, eventually, lead to the onset of lethal disease. A molecular marker of cp BVDV infection is a high-level expression of the replicative NS3 protease/helicase that together with NS2 is derived from NS2-3. Here, we present evidence for NS2-3 autoprocessing by a newly identified cysteine protease in NS2 that is distantly related to the NS2-3 autoprotease of hepatitis C and GB viruses. The vital role of this autoprotease in BVDV infection was established, implying an essential function for NS3 in pestiviral RNA replication which cannot be supplied by its NS2-3 precursor. Accordingly, and contrary to a current paradigm, we detected almost complete cleavage of NS2-3 in noncp BVDV at early hours of infection. At 6 to 9 h postinfection, NS2-3 autoprocessing diminished to barely detectable levels for noncp BVDV but decreased only moderately for cp BVDV. Viral RNA synthesis rates strictly correlated with different NS3 levels in noncp and cp BVDV-infected cells, implicating the NS2 autoprotease in RNA replication control. The biotype-specific modulation of NS2-3 autoprocessing indicates a crucial role of the NS2 autoprotease in the pathogenicity of BVDV.
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ABSTRACT: Multiple sequence alignment can be a useful technique for studying molecular evolution, as well as for analyzing relationships between structure or function and primary sequence. We have developed for this purpose an interactive program, MACAW (Multiple Alignment Construction and Analysis Workbench), that allows the user to construct multiple alignments by locating, analyzing, editing, and combining "blocks" of aligned sequence segments. MACAW incorporates several novel features. (1) Regions of local similarity are located by a new search algorithm that avoids many of the limitations of previous techniques. (2) The statistical significance of blocks of similarity is evaluated using a recently developed mathematical theory. (3) Candidate blocks may be evaluated for potential inclusion in a multiple alignment using a variety of visualization tools. (4) A user interface permits each block to be edited by moving its boundaries or by eliminating particular segments, and blocks may be linked to form a composite multiple alignment. No completely automatic program is likely to deal effectively with all the complexities of the multiple alignment problem; by combining a powerful similarity search algorithm with flexible editing, analysis and display tools, MACAW allows the alignment strategy to be tailored to the problem at hand.Proteins Structure Function and Bioinformatics 02/1991; 9(3):180-90. · 3.39 Impact Factor
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ABSTRACT: The aim of this study was to examine the prevalence of depression and anxiety following coronary artery bypass surgery (CABG) and to see how those patients with depression and anxiety differ in sleeping pattern. The individual reaction to sleep loss was tested as a predictor of certain emotional symptoms in the follow-up period. Thirty-eight males, between 45 and 68 years, were interviewed prior to, and 1 month after, surgery, and received a questionnaire at the 6-month follow-up. Eighty per cent scored moderate anxiety prior to surgery and six patients were depressed. An anxiety-prone individual reactivity persisted in the same patients in 38.9% (n = 14) following CABG, with significantly more sleep disturbances, firedness, energy deficits, immobility, and lower degree of quality of life (QoL). Sad/depressed mood or cognitive/behavioural fatigue symptoms as reactions to sleep loss were predictors of sleep problems and daytime sequelae, whereas a higher postoperative NYHA class was predicted by cognitive/behavioural fatigue and dysphoria reactions. Being less refreshed by sleep on final awakening prior to surgery related to 44.5% of the variance in QoL outcome 6 months following surgery. In conclusion, an anxiety-prone individual reactivity is significantly associated with sleep disturbances. Reactions to sleep loss prior to surgery are associated with emotional distress after surgery.Scandinavian Journal of Caring Sciences 02/1999; 13(2):137-43. · 0.89 Impact Factor