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Modeling of the 5’ Nontranslated Region of Coxsackievirus B1. Wade Schulz Biology Colloquium Spring 2003. Introduction. Coxsackievirus RNA Secondary Structures Computer Modeling Analyzing Results Enzymatic Probing. Small virus made of protein and RNA
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Modeling of the 5’ Nontranslated Region of Coxsackievirus B1 Wade Schulz Biology Colloquium Spring 2003
Introduction • Coxsackievirus • RNA Secondary Structures • Computer Modeling • Analyzing Results • Enzymatic Probing
Small virus made of protein and RNA Poliovirus, coxsackievirus, echovirus 3 Forms of Poliovirus 23 Coxsackie A viruses 6 Coxsackie B viruses 28 Echoviruses 4 other Enteroviruses Second most common viral infection Led by rhinovirus (common cold) ssRNA(+) Protein coat Enterovirus http://www.cdc.gov/ncidod/dvrd/revb/enterovirus/non-polio_entero.htm
Associated Infections • Aseptic meningitis, encephalitis • Myocarditis, Dilated Cardiomyopathy • Type I diabetes • Amyotrophic Lateral Sclerosis (ALS) • Post-Polio Syndrome • Chronic Fatigue Syndrome
Coxsackievirus B1 • Two types used in experiment • 1.24 • Wild type virus • Causes acute infection as well as chronic disease • 2.17 • Mutated form of virus • Causes acute infection but no chronic disease
Mouse Model 2 weeks Viral replication Acute inflammation & damage Inject CVB1 into newborn mice Acute infection Hind limb flexion deformity/gait 1-6 months Chronicdisease
Mutational Change • What changes does the mutation cause in the viral structure • Does the structural change affect regulation
RNA Secondary Structures • Caused by bonding between bases on RNA • Creates stems and loops in RNA • Double-stranded stem • Single-stranded loop
Computer Modeling • MFold • Created by Michael Zuker • Uses algorithms to compute lowest energy models to create structures • Also known as a “squiggles” plot • GeneQuest • Part of Lasergene Suite • Only provides folding for one energy level
Computer Modeling • RNA sequence is entered into database • Folding conditions are set • 37°C, energy increments • Server folds based on Zuker or other algorithms
Data Analysis • Stems and loops were identified • Beginning and ending nucleotides were recorded • Most common stems are assumed to exist • Enzymatic probing done to determine actual structure
Stem Changes • Repeated stem changes were noticed between 1.24 and 2.17 structures • Change was noted in stem where mutation was present
Enzymatic Probing: Primer Extension • Use enzymes to cleave RNA at specific points (single strands) • RNase T1 - Guanosine • RNase U2 - Adenosine • RNase A - Pyrimidines • RNA then placed in gel to determine lengths
Primer Extension and Gel Analysis Hsue, et al.
Conclusions 1. Presumptive evidence from computer modeling that 1.24 and 2.17 forms differ 2. Stem and loop just upstream of translational start may function in regulation and tropism