Multiplication of Animal Viruses
5. Maturation and Release
nonenveloped released thru ruptures in OM...leads to cell death
capsid pushes through PM..buds...cell usually doesn't die
envelope develops around capsid by budding
starts with assembly of protein capsid
4. Biosynthesis of RNA Viruses
Retroviridae
in oncogenic retroviruses the provirus can convert host cell into a tumor
integrated into host cell chromosome as a provirus which gives it protection from antivieral drugs
carry reverse transcriptase which uses viral RNA as template and degrades original viral RNA
Lentivirus
infect vertebrates
Reoviridae
double stranded RNA
respiratory and enteric systems
Rhabdoviridae
single antisense strand of RNA
bullet-shaped
rabiesvirus
Togaviridae
enveloped
contain singe sense strand of RNA
arthropodborne, arboviruses or alphaviruses
Picornaviridae
contain RNA dependent RNA polymerase
new strand is antisense strand
RNA w/in virion is callsed sense strand because it can act as mRNA
smallest viruses
single-stranded RNA
poliovirus
multiply in host cell's cytoplasm
4. Biosynthesis of DNA Viruses
DNA Viruses
Hepadnaviridae
synthesize DNA by copying RNA using viral reverse transcriptase
cause hepatitis and contain DNA
Papovaviridae
some Papillomavirus can ause cancer
name from papillomas (warts), polomas (tumors) and vacuolation
Herpesviridae: spreading appearnce of cold sores
Kaposi's sarcoma, primarily in AIDS patients
Roseolovirus: Roseola
Cytomegalovirus: CMV Inclusion Disease
Lymphocryptovirus: infectious mono
Varicellovirus: chickenpox
Simplexvirus: cause cold sores
Poxviridae: skin lesions--cow pox and smallpox
Adenoviridae: common cold
7. released from host cell
6. maturation...assembles to form complete viruses
5. synthesis of capsid proteins in cytoplasm
4. transcription and translation of "late" viral genes...capsid and structural proteins
3. transcription of viral DNA...translation..
1-2. viral DNA released into the nucleus of host cell
Hepadnaviruses
Adenoviruses
papoviruses
Herpesviruses
3. Uncoating
poliovirus--uncoating starts to happen while virus is still attached to PM
separation of viral nucleic acid from it's protein coat once the virion is enclosed w/in vesicle
2. Entry
enveloped viruses can enter by fusion: envelope fuses with PM and releases capsid into cell's cytoplasm
HIV
by pinocytosis
1. Attachment
receptor forparticular virus varies from person to person
receptor sites are inherited characteristics of the host
enveloped--influenza--spikes
adenovirus--icosahedral--small fibers at corners
attachment sites are distributes all over virus
