Lecture 3 - Viral Genome - Microimm 2500
Lecture Overview
Page 2: Course Information
Topic: Viral Genomes
Instructor: Dr. J.D. Dikeakos
Course Code: MNI 2500
Program: Schulich Medicine & Dentistry, Microbiology and Immunology
Contact: Jimmy.dikeakos@uwo.ca
Page 3: Review of Key Concepts
Physical Measurement: Importance in virology
Fluorescent Proteins: Use of GFP as a tag
Viral Genome and Protein: Integration of genes to create detectable proteins
Page 4: Recap
Summary of key concepts related to fluorescent proteins in virology
Page 5: Lecture Objectives
Understand Viral Genomes: Types and functions
Importance of Genome: Role in viral classification and function
Baltimore Classification: Overview of viral genome classification
Transmission of Genetic Information: How DNA and RNA genomes convey information
Page 6: Themes in Virology
Necessity for Survival:
Packaging genome inside a particle
Using the particle for genome transfer
Ensuring long-term viral survival
Historical Context: Viral genome recognized as genetic code since 1950s
Page 7: Viral Infectious Cycle
Role of the Genome: Key orchestration of viral life processes
Virions: Serve as vehicles for transmission to new hosts
Page 8: Hershey-Chase Experiment
Purpose: Demonstrate whether nucleic acid or protein specifies virus production
Methodology: Infection with radioactive precursors, blending, and separation to analyze components
Page 9: Modern Proof of Genome Importance
Use of cyanine dye to track viral genomes during infection processes
Page 10: Baltimore Classification
Overview: System for classifying viruses based on their genomes
Page 11: Key Concepts of Viral Classification
7 Virus Groups according to Baltimore classification
mRNA Requirement: Essential for translation on host ribosomes
Reading Direction: mRNA read in the 5’ to 3’ direction
Page 12: Viral Genetics Recap
Translation Process: From DNA to mRNA to protein
Non-linear Process: Viruses do not follow traditional genetic dogma
Page 13: Common Goals of Viruses
Production of mRNA: Core objective for all viral types
Classification of Viral Genomes: Diverse forms of genetic material presence in virions
Page 14: Strand Definitions
+ Strand: Ready for translation (mRNA)
- Strand: Complementary to + strand
DNA Strand Types: + and - strands in DNA genomes
Page 15: Types of Genomes
Categories of Viral Genomes:
DNA or RNA but not both
Diversity of groups observed
Page 16: Discussion on Genomic Evolution
RNA vs. DNA Viruses: Evolutionary timeline and diversity
Page 17: DNA Genomes Functionality
Overview of how different DNA genomes function in host systems
Page 18: Importance of Genomes Recap
Key Role of Genome: Central aspect of viral function
Page 19: Double-Stranded DNA Genomes
Mechanism:
Requires host RNA polymerase
Interactions with early viral proteins
Page 20: Example of dsDNA Virus
Polyomaviridae: JC Virus impact on human health, particularly in immunocompromised patients
Page 21: Larger Genomes in Viruses
Poxviridae: Variola Virus responsible for Smallpox; larger genomic structures
Page 22: Gapped dsDNA Genomes
Mechanics: Filling gaps in the genome and subsequent transcription processes
Page 23: Hepadnaviruses (Hepatitis B)
Transmission and Impact: Highly infectious virus that can cause severe liver damage
Page 24: Single-Stranded DNA Genomes
Limitations: Cannot directly copy to mRNA; use of host machinery is critical
Page 25: Parvoviridae Examples
Focus on infections in pets and impact on animal populations
Page 26: RNA Genomes Overview
Lack of host enzymes leads to unique challenges for RNA viruses
Page 27: dsRNA Genomes
Translation Process: Requirement of viral polymerase
Page 28: dsRNA Impact
Rotavirus: Major cause of gastroenteritis in children, with serious health implications
Page 29: Single-Stranded (+) RNA Genomes
Immediate Translation: Utilizes host machinery without additional enzymes needed
Page 30: Poliovirus Example
Medical Significance: Causes known disease paralysis
Page 31: SARS-CoV-2 Overview
Classification within the Coronavirus family
Page 32: Reverse Transcriptase Role
Functionality: Transforming RNA into DNA for viral replication
Page 33: Retroviridae Class
Mechanism: Integration with host DNA for replication processes
Page 34: (-) RNA Genomes Characteristics
Requirement: Need for replication through viral polymerase
Page 35: Examples of (-) RNA Viruses
Discussion of examples such as Paramyxoviridae and Orthomyxoviridae (Influenza)
Page 36: Ebola Virus Characteristics
Viral Mechanism: Importance of viral polymerase in mRNA production
Page 37: Additional Viral Genome Complexity
Discussion on the need for robust genome structures for efficient replication
Page 38: Summary of Core Concepts
Take Home Message: Creating a comparison table for genome types and their functionalities in context of viral families and individual viruses.