Virus Genetics Flashcards
Gene Expression
No operons
Expression is induced by TF binding to promotor
What determines tissue specificity?
TF in that particular tissue
Genome structure: Simple v. Complex
Simple: 1 promotor, linear, one strand contains genes
Complex: Both strands has genes, overlapping, each with own promoter
What makes viruses genomes efficient?
No non-coding regions Overlapping reading frames Translational frameshifts Splices Polyproteins
Compare DNA and RNA viruses in terms of mutations
DNA is more stable, RNA more prone to mutation
Types of mutations and interesting results of mutations
- Point, deletion, insertion
- Integrate mutated genome into host genome can cause activation or repression of host genes
- some mutations only allow virus to grow under certain conditions
Complementation
A gene function of one virus replaces a mutated or missing gen of another
Allows non-viable viruses to be viable
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Phenotypic mixing
Exchange of caspid proteins
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Pseudotype
genetic material from one gets into the caspid or envelope of another
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Recombination
Exchange between homologous portions of genomes
Reassortment
the rearrangement of parts of a segmented genome to form a new set of segments
interference
infection by one virus prevents infection by another
Blocking receptors, competition for resources, production of interferons or other antiviral agents
Gene Therapy
correct or prevent disease by transfer of appropriate genes to patient
Modified viruses used as vectors
Used mainly for congenital diseases that lacka single gene
Problems with gene therapy
Short duration of expression
Low efficiency of gene transfer
Sever inflammation as result of virus
Malignant diseases sometimes
