Lecture 1: September 10th, 2012
Transcription can be done via cellular enzymes or coding their own, but they absolutely need host cells
translational machinery (host cell ribosome) in order to make protein
A virus absolutely needs a host cell in order to replicate. Has to have a genome.
Hijacks cellular machinery in order to make its own protein
first problem: how do you get inside a cell to infect it?
o If it can get inside of a cell its considered susceptible
o Permissive: if it can replicate inside the cell.
o Not all susceptible cells are permissive but all permissive cells are susceptible
problem 2: needs appropriate machinery. RNA virus replicates in the cytoplasm, DNA virus replicates in the
o not ALL but for the most part
VIRUS often suppress/interfere host gene expression: How? Having the ability to replicate in the cytoplasm
(doesn’t need host machinery except ribosome) no competition for translation. Tnraslational machinery suppress
host functionality. It can interfere with host mrna transcript… (cap snatching steal 5’cap off cellular mrna; cellular
mrna can’t be translated). Retrovirses whenever u have an integration of a viral genome into host dna, its random.
It can interfere with host gene expression dna viruses encode a lot of invasion proteins things like protein
mimicks, cytokine mimicks enable virus to maintain sustain in the cell for longer period of time b4 recognized, b4
cell dies before replicating virus genome efficiently. Why? It wants to keep all of the resources (host cellular
machinery) for viral protein sythesis, viral genome replication.
various surfaces: simple squamous epitheliam (gas/nutrients exchange), and other surfaces etc…
*Definitions are good for quiz questions
Tropism: ability of a virus to invade/infect a particular cell type/tissue. Some viruses are tropic to the respiratory
Host range: list of species that a virus can infect
Phagocytosis: large molecules. Endocytosis: smaller molecules.
Influenza ends up in the endosome and the acidification of the endosome produces a fusogenic protein. Fuses viral
envelope with endosome membrane and spills all of viral genomic proteins into the cytoplasm which go to the
Adenovirus binds to receptor on cell surface, taken up into endosome, acidification activates proteases that chews a
pore in the endosome, releasing virus into the cytoplasm. Hijacks cellular machinery and gets delivered into
Poliovirus: nonenvelope virus. Gets taken into the endosome. It has a VP1 (viral protein 1) that channels/burrows
into membrane that creates a pore so it can inject its genome into the cytoplasm.
Paramyxoviridae: when the virus binds to its receptor it triggers fusion protein to bind to cell membrane which is
how virus gains entry into the cell
Assembly and Egress (after viral replication)
problem: must encapsulate and be protected from the time they leave a cell to when they enter the environment
outside the cells and have to find another cell that they can infect
problem 2: viruses have to be able to escape the infected host cell. If you are an envelope virus you use the cellular
machinery inside the host cell to bud off. Nonenvelope viruses fill up the host cell and the cell bursts and they are
released passively into the environment.
Poliovirus binds to receptor infects host and its genome gets injected into the cytoplasm
o Genome can be directly translated and it makes a bunch of protein. At the same time its genome gets
replicated. Proteins and genome assemble and are expelled from the cell.
adenovirus is a DNA virus
o gets into nucleus, replicates, proteins are made and must go BACK inside the nucleus to assemble.
Then it has to leave the nucleus
fusion: the viral membrane fusing with the infected cell. Fission: when the virus buds off. Separation of the virus from its infected cell.
Herpes: envelopes and deenvelopes a bunch of times. A DNA virus. Starts off in the nucleus, buds off, goes into
endoplasmic reticulum, enveloped, deenvelopes to get out of ER and acquires proteins, enters golgi apparatus
acquiring and enveloped, buds off (double enveloped) and buds off cellular membrane leaving it with a single
Nonenveloped viruses: hijack cellular machinery but in doing that it shuts down host gene expression.
Lecture 2: September 13, 2012
Virus has a very small genome; it needs a way to pack into very small amount of space; there are strategies that
virus uses in order to package everything it needs to encode in small amount of genetic information. Get their
genome replicated get their gene express in such a way that recognized and translated by host ribosome’s
Small genome: collect their genome and package it and if its larger complex, it is more difficult & not efficient.
Quick replication (“get in and get out”) b4 our immune system response. Smaller genome easir to go to nucleus. It
is longer to take care a larger genome.. (think of passing a small vs. large note in class) mistakes are prone in larger
genome. Packaging ** protein capsid; limit physical space in that cozyhedral capsid. Downside: limited genetic
material; u cant have functions, cant encode many genes, cant do many things. pox viruses; 200 genes, can create
so much more. Ex) have genes that create manipulate the dna immune response, all sorts of things to their host cell.
small viruses with 3 or 4 or 5 genes,cant do that. DIFFERENT LIFE STYLE = genome difference. Genome is
primary classfier for viruses
1 way of classifying viruses is using the Baltimore classification system; using the nature and polarity of the viral
genome. Class 1; double stranded dna (look similar to host cell dna cellular dna). Class 2: single stranded dna
genome.packaged genome is single stranded but need to become ds in the nucleus to be replicated and access our
enzymes. So theres a ds intermediate that is copied to produce a single stranded version that gets packaged.
Class3; ds rna genome class; AND segmented genomes (influenza).. these viruses have multiple individual
segments;each segment is transcribedthe NEGATIVE sense is copied so the single + sense mrna is recognized by
our ribosome’s and translated to protein. 4: negative sense rna genome class5: + sense rna genome with – sense
rna intermediate that is used as a template for making more + rna genomic copies. Class6; positive sense rna
viruses with a dna intermediate
We are as normal: we have ds DNA (has – and +); and we make positive strand MRNA= that encodes the protein..
this is the copy of the – strand. The copy is the complementary strand.
Package: along with the genome, u put other things in the viral particle. Structural proteins… make up the structure of
the particle there are nonstructural proteins like the polymerase that may or may not be present in that particle.
Non structural protein: only made in the host cell, function in the host cell, but not present in the progeny ***
DNA viruses: they can use the polymerases that we have. Don’t need to code for this protein OR package. Viruses are
more dependent on the host cell. mostof the cells in the body are not expressing dna polymerase right now.. b/c they
are not dividng (replicationg) dna viruses that do not encode a polymerase they only replicate in certain host sites that
DO constantl divide (ex. Skin epithelial cells) b/c they need a polymerase. Exception: dna viruses that do not encode a
polyermase who can infect cells that DON’T normally replicate by CAUSING the host cell to replicate. Pepalomavirus
they build a wart in ur skin, they need dna polymerase; they cause skin to replicate and express more polymerase for
their own purpose. A growth (# of cells increase) ; causing cancer. They are able to use host cell enzymes in order to
mediate transcription; that’s beneficial b/c they don’t need to encode for that; not wasting space in their genome
encoding those; GENOME MUST GO TO NUCLEUS. except for pox viruses they replicate in cytoplasm need to
have a big genome; make ALL of their enzymes.. they don’t use host. The drawback of this strategy is that they need
the host cell to be actively making those enzymes to be replicating so polymerases are available to viruses in order to
replicate their genome. All of these are found in the nucleus so they need to get their genome into the nucleus to be
replicated. Rna depend rna poly: only evolved once & all viruses use some versions derived form the original and never an
improvement on the poly. Error prone.. than dna pol. Problem of copying.. another limit to the size of rna genome b/c
these viruses cant maintain a big genome because so mistake prone.
RNA viruses: independent! Replicate in cytoplasm. In theory, they can replicate in any cell; they just need ribosome’s.
tend to have smaller genomes and simpler genomes but dedicate a lot genome to polymerases!! They cant do many
other things; beause devoting a lot of their genome to polymerse no matter what. DNA viruses have a broader range in
size; smaller (don’t encode polymerase) & very large (encode all sorts of things)don’t need the host cell to be actively
dividing. They have to encode a viral rna depedent pol b/c we dont have them (ENCODE THEIR OWN) Host cells
don’t have rna dependent pol; viruses need to bring it with them (packaged in their virion) or have to encode it so they
can make it . Transcription vs. replication
Class i: why is it advantageous for poxviruses to replicate in the cytoplasm?: can effectively shut down host
machinery; u don’t care about the host is doing,host tracription. So u can shut down host cell processes and ensure that
u are actively replicating. downside: has to encode all of the enzymes it needs to replicate its genome.
DNA genome into the nucleus may or may not use our enzymes to replicate their genome. Exception: poxvirus. They
encode additional enzymes along with their polymerases to replicate in the cytoplasm.
Class 3: instead of 1 long strand, multiple strands, each segment encode 1 mrna which translate into individual
proteins . they never quite disassemble. Have their own polymerase RNA VIRUS=OWN POLYmerase. ▯live
inside a capsid, and makes copies of ds segments, and make + single stranded mrna bits to be translated. We never
have ds rna in our cells.! We have receptors/protein that surveil our proteins that look for ds rna b/c this is a
pathogen associated= indication of infection. Viruses have ds RNA have to hide that from detection system and 1
way to do that si to hide them in viral particle all the time.
RNA Virues: Ds RNA incoming genome ▯ ds rNA made from that or single stranded mrna that are translated
there’s never DNA..
Class 4: Simplest. Their genome is + sense so it’s the same strand as the could be translated! Don’t have to bring
any protein w them. They have to encode a polymerase b/c they are rna viruses.. but they DON’T BRING IT
WITH THEM THEY DON’T PACKAGE IT. b/c all they do is put genome in cytoplasm, its recognized by
ribosome’s▯translated ▯make the 1 s protein: polymerae. Polymerase comes back and recognize the + sense genome
and replicate it.
Antigenome: () sense copy. This is copied again and agin to make + sense progeny genomes (mrna).
Subgroup: Polymerase will transcribe parts of the genome to make mrna’s of subunit bits, and they regulate the
amount of protein made.
polycistronic mrna: rna IS the mrna. Once virus enter the cell it acts as rna; recognized by host cell ribosome and
translated into 1 long protein and can be cleaved up into smaller components (smaller proteins that used for various
aspects) B) transcription regulation; actively regulate which genes are transcribed at which time within the life
cycle; different strategies; subgenomic mrna, mediate ribosomal framshift..etc.
(+) sense can access to ribosome’s, it can make protein right off the bat, no need to bringpolymerase, because
polymerase will be made. Polymerase make copies and produce (+) sense mrna.
Class 5: package 1 strand of RNA, but it’s the () sense.
() sense genomes have the template for trnscription.. so it brings its polymerase to make mrna which are translated
and this include polymerase. Gotta replicate its genome full length and make the + sense (antigenome) copied to
make () sense.
This doesn’t code for protein. They need RNA dep rna polymerase in their genome encoded, AND packaged. The
viral particle has this polyermase protein. When get inside the cell, that genome is already has a polymerase and
this polymerase makes mrna in cytoplasm, makes more polymerase, and then copy the genome, the () genome is
made to a full length postivie sense antigenome which serve as a template to make negative sense genome progeny
for packaging. first step in replication: to use their negative sense genome as a template for m RNA & for
making a template to replicate their genome. Segmented genomes like influenza replicate in nucleus
and each segment encodes for a different mrna. All negative sense rna viruses need to bring with them?: rna depedent rna polymerase. transcribe that positive
sense, or they cant replicate their genome
Positive sense rna virus; no. they look exactly like mrna. Can be immedisately translated and make their rna
dependent polyemerase; it’s one less thing to package
Antigenome; is the other strand, it is the template to make the genome . ex) ()sense is packaged, and the
antigenome is (+) to make more () sense
Classification is based on w/e is PACKAGED.
Replicate FULL LENGTH: ▯make progeny
Replicate SHORT BITS of a gene: ▯create mrna a part of a whole genome (TRANSCRIPTION)
Use SAME polymerase to do that!
Class 6: genoem in the viral particle + sense rNA. Reverse transcriptase turns the rna genome into ds DNA. This
is exception of before stateent saying there is no dna in the RNA stuff. dsDNA is now like us, and go to the
nucleus. And integrate into our genome and become part of us! ▯make mrna(+) sense ▯make proteins ▯make (+)
sense that is packaged
They can replicate in 2 different ways: 1) piggyback on us our genome. We replicate the viruses by copying our
genomes. Retrovirs integrate genome and the cell make progeny; the progeny cells have that viral genome. 2) they
use our enzymes to make rna copy, that can be packaged for transmission.
they have a diploid (+) sense rna genome. Diploid= two copies of the same thing. We are diploid of two
chromosomes that are quite the same but very similar.
Segmented genomes= several pieces but they are each different. Purposely put two copies of the same thing into
the viral particle= diploid. 2 copies of the same positive sense, single stranded, 2 copies. 1 or both, Turn into ds
DNA and get put into the genome.
retrovirus: viruses that bud from the surface of the cell. (+) sense comes out of nucleus, transported to
plasma membrane, enveloped, into the virus, buds out of cell without killing it. b/c it is an envelope virus
Class 7: they are double stranded dna that are gapped.. two strands that overlap to keep it as a circle. Some
stretches are single stranded..Viral MRNA (+) sense for proteins are made. But a full length pregenome rna is made
that is then used as a template for reverse transcripase to make a dna genome that is packaged. and use rna as a
temlate to make more; and reverse transcribe that back to dna in order to replicate their genome.
they don’t integrate into the genome of the host cells
go back and forth b/w rna and dna
We don’t cover this.
Progeny virions: all the components of the virus and capsid (vessel to deliver the genome)
• Table 9.1: dna viruses; some exclusively use our enzymes to copy and translate their mrna.. it varies. Many use
our accessory proteins even if they have their own polymerase. They use TFs that regulate thexpression of their
gene. they use cellular AND viral proteins in order to replicate their genome exception of pox viruses which
don’t require any cellular enzymes to replicate their genome; b/c they have to encode it all.
ORE: depending on where u start reading the start codon, u get a completely different protein.
Reinitation: during translation when the ribosome is going along and reading, it can stop and reinitatie
downstream. 2 coding regions, it reach a stop codon and stay there, if theres a downstream start codon, it retinitatie
translation of a different protein
Suppress/termination: ribosome skipping over stop codons. Sometimes it’ll stop and release that protein, or it’ll
keep going and make a new one..
Proteolytic process; 1 long poly protein that is cleaved to multiple protein
IRES: viral encoding structural motif which enable ribosome to read the mrna transcript w/o 5’cap. U can have
multiple IRES in your transcript and ribosome can read at various different spots. Lecture 3 September 17th
POSITIVE STRANDED RNA VIRUSES – LECTURE 1
positive strand is the strand that codes for proteins. The same sequence read by ribosomes to encode protein
negative strand: template that rna dependent polymerases use to generate the positive strand.
Positive strand RNA viruses have a positive stranded genome> you need the negative strand as a template to make
the positive strand.
Simple positive strand: full length positive strand and negative strand antigenome
Alphaviruses (don’t really cover in this course)
Wtf? Nino viruses? Nid?
o Meaning nested
o Subgenomic mrnas made from the negative strand antigenome
Picornavirus replication cycle
o Simple viruses
o Attachment and entry, replication and production of progeny which then have to get out of the infected
o Dock onto cell that they can bind to based on a receptor. Inject their positive stranded RNA genome into
Because it’s positive, the genome itself is infectious and all it needs is to get INSIDE the cell,
then rna will translate it right away
Non structural proteins (polymerase etc) serve to replicate the genome of the virus and make
many copies. The positive stranded genome is copied to make a negative stranded antigenome
which is then used to make tons of positive strand copies.
Wait for the cell to lyse and then all the progeny is released.
They make the host cell so sick that it’ll either kill itself through apoptosis or die through necrosis and then
releases all the viral progeny
The viral capsid is a protein capsid (don’t talk a lot about structure in this course)
The structures are made of repeating protein units that have evolved to spontaneously assemble
The viral genome is one long open reading frame. The ribosomes read it all the way through and translate this large
polyprotein. Within the polyprotein there are proteases and the proteases cut themselves out of the protein and go
find sequences with the rest of the protein that they recognize and snip the protein there.
the one thing all viruses need from their host is translation
most positive stranded viruses do not have CAP mrna. They mess up the host’s ability to translate …they recognize
the cap banding complex and clip it so our cells can no longer recognize CAP. The virus wants to stop host
translation so they can totally take over the cell and also weakens the hosts defences. The host cell, when infected
tries to make the antiviral proteins so if you stop translation, this won’t happen.
Cutting the protein only prevents the host from translating it doesn’t necessarily cause the virus to enable
translation for itself. The virus has a highly structured rNA that sort of mimics the preinitiation complex (which is
made up of ribal proteins)
o Skip over the CAP step and they have the second structure that allows for the initiation of translation
without needing the CAP protein
you may never get the same cold twice because your immune system will prevent you, but you keep getting it
literally because there are so many viruses out there.
Enteroviruses enter the GI tract through the mouth (i.e. contaminated water)
Poliomyelitis enterovirus (enters the body orally)
many people don’t even recall having symptoms
small proportion, however if millions of people are getting infected then it becomes a large number of people
intercostal muscles: affects your ability to breath
The Iron Lung
put people in an iron lung with seals around your neck, and it helps to expand and contract your lungs allowing
you to breathe. You stay there until (if) you are able to breathe on your own again.
This really sucked so it lead to the development of the polio vaccine
There are many viruses that you’d rather be infected with when you’re very young than not be infected when
young and then infected as an adult
o Reason is still unknown
children that aren’t exposed to polio and are later exposed as an adult are much more likely to develop paralytic
sanitation argument doesn’t hold up because now that everything is clean, people are not getting infected at a
young age but rather when they are older
we have now eliminated two viruses in the WHO
o small pox
o Rinderpest (affects hooved animals)
Polio is the current effort to irradicate
measles is another one being considered
we can’t seem to quite get rid of polio although the numbers are quite low…probably because there are a lot of
people who have it but don’t have symptoms so they don’t know they have it therefore it’s floating around
one of the main arguments for not going after polio as the target for irradication
o it is too simple of a virus
o advantage to eliminating smallpox was that once we got rid of it we could stop vaccinating cuz it was
o we still vaccinate for polio here: the worry is that it can come back. The reason is because you can
MAKE polio. It’s an infectious genome. All you have to do is make that RNA and put it in a cell and
that cell will make an infectious genome.
o He made it himself: took a sequence of polio, broke it down, and ordered enzymes, proteins over the
internet using a credit card. Pasted them all together. Ordered a kit of translation machinery from rabbit
cells. Mixed everything together in a tube and voila, he had infectious polio in a tube.
o He said a disgruntled graduate student could make this in his basement. Anyone with that much
knowledge could make it again and release it.
o It’s harder to make measles because it’s a negative stranded virus
The prof’s lab makes viruses all the time now like that so….uh oh….
Lecture 4: September 20th, 2012
Positive Stranded RNA Viruses – Lecture 2
interesting property: how they replicate
Poliovirus ; + strand virus. Interesting fact is how they replicate when these viruses are in the cell there is a large
increase in membrane boundvesicles in the cell; debate whether this is part of the defense process by the cell or
induced by the virus. Leaning more to induced by the virus; reorganization of the internal characteristics.
when these viruses infect a cell, there’s a large increase in membrane bound vesicles within the cell
o is this part of a defensive process or is it something induced by the virus? Leaning towards something
induced by the virus – reorganization of internal membrane of the cell. the reason why they do this ;
The virus replicates on these surfaces. o The viruses particles (the black) are forming on the surface of these membranes. Have to do with
organization of the polymerases for the viruses. All polymerases have a general term; smilar structure.
Like a hand. Finger thumb palm. all polymerases have similar structures. Compared to a hand (the
groove, between the fingers and the thumb, is where catalytic activity is)
all polymerases as an enzyme only asorse once. Evolved once. They are structurally related (i.e. rna dependent rna,
dna dependent dna, reverse, etc) but types have evolved.
Poliovirus have been all related; diverged into different type of polymerase all structurally related however.
RNA dependent rna polymerase of Poliovirus and pos strand viruses: they associate with another protein and that
protein anchors them onto a membrane. They array themselves on a surface which forms this lattice (a catalytic
surface). This Question… ▯
^ this is why These viruses can replicate so quickly because they ed this important catalytic machine that copies
their genome; they’ve arrayed on the surface so their RNA strands can move through and be copied not just one at
a time but strand will be replicated multiple times at once—get progreny of different lengths Therefore you have
copy strands of different lengths spooling out of this surface. 1 is copied many polymerases 1 antigenome is
copied by many polymerase all at once, to produce many copies. It doesn’t have to find another polymerase.
Most polymerases appear to be anchored somewhere: they move the template through them, it’s the template that
moves and the copy that comes out of the catalytic groove and the polymerase is stationary; Protein anchors them on a
membrane. Virus gets many of these proteins and on the surface; forming a lattice. A catalytic surface.youtube it! a
polyermase that works; diagam of animated cartoon. Template as a long linear dna; showing a polymerase attaching to
it; but its more likely that they are already anchored.
** Property of (+) stranded RNA viruses: strand switching.
o No segmented genome
o Analogy: room is surface, if each of us is a polymerase we represent an infected cell. If he had paper
that he has written a recipe to make muffins, hand it to you to make copies. As you read it you pass it on
and the next person can grab it and they can make copies, etc. the first one would pass through the room
and very many copies would quickly be generated, and another person would quickly get the copied
info and copy it.etc. in fact the first one may not be responsible for all copies because you can make
copies of copies. That is why this is so efficient, because many copies can be occurring at one time.
Also there could be a lasanga recipe flowing around and u might copy that instead. (these different rna’s
could be the host’s , Coinfection. (infected by 2 different pos strand viruses ▯ errors)
o Pos strand single stranded rna genome; only 1 piece of rna that encode 1 poly protein; structural
proteins, and encode nonstructural proteins. From 1 genome.
o 2viruses will have 2 different genomes.
o affected by a positive stranded virus: increase in mutation; error prone; rna polymerase have no
proofreading. Cell is full of rna already; co infection; same cell become affected by two different
positive stand viruses; single stranded positive strand rna gene. And only one piece of rna; encoding one
protein structural protein and encodes polymerase; accessory proteins; making the whole thing going.
drawback of the poliovirus; virus with mutation already and it is non pathonogeic.
o Vaccine virus co infected the cell by wildtype polio , they can strand switch and produce new polio
o What is someone introduces another paper that has a recipe for lasagna? Eventually it gets crowded and
someoneee will make a mistake. In a cell, this happens, mistakes occurs, many mutations occur,
These other strands can come from the host
Another source can be coinfection
Keep in mind: this virus is single stranded i.e. has one strand of RNA that codes for everything
o rNA polymerases do NOT have a proof reading function, and therefore are error prone. Highly Mutagenic: reasons:
at least two sources of confusing rna in a cell
Transcription problem (no proofread)
Potential for deletions (drop a strand, pick up the same strand at a different place, etc)
Can strand switch between different viruses with different RNAs and then you get chimeras
Most of that would be junk
o Some of those can exist and will be different than the parent.
o i.e. classic sample. Bovine Viral Diarrhea Virus: Bovine viral diarrhea virus; Pos strand Rna virus
usually non pathogenic. Affecting a cow; cross the placental and affect the fetus (if pathogenic) this
virus becomes self and the cow is infected but the immune system does not recognize the virus at all;
never clearing the virus; and chronically affected their whole life. Antigens that it sees before birth is
regarded as self. So viruses or other pathnoges that affect the fetus; is viewed immune system as self.
This virus uses this to exist.
o Because it is positive stranded viruse; it is highly mutagenic; causing its pathogenic; affecting the host
(bottom of the slide) the cow figure.
o if it infects cow it can cross the placenta and affect the fetus.
o Anything seen before birth is regarded as “self”. Viruses that infect the fetus are viewed as self. The calf
is infected but the immune system doesn’t do anything about it, therefore they are chronically infected
for their whole life.
o There are no symptoms of this virus, and there’s no damage, the virus itself doesn’t kill cells; just
replicates and lives in the GI tract. And the cow will pass to their baby so and so on.
o Sometimes something goes wrong (because it’s positive stranded and therefore highly mutagenic).
Once in a while it will strand switch with host RNA. If the strand switches with the host mRNA which
has a different cleavage site (acquire different protease cleavage sites) will change how the virus
interacts with the host they become pathogenic to the host
o The virus can only regulate the abundance of proteins by regulating stability of proteins/frequently they
are cut up.
o How effieicntly the polyprotein is cleaved changes the the abdunaces of the parts (the different
proteins) this changes how the virus interacts with the virus
o Therefore all of a sudden these viruses become pathogenic to the host. Become too aggressive, damage
the GI tract and lead to very severe diarrhea
Another family of + strand viruses
o Arbovirus: any virus that is spread by (usually) biting (probably fluid transfer)
o All the viruses in the chart are arboviruses
o West Nile virus; another outbreak in north America mosquitoes
o Hep C (exception; not spread by insects.)
The insect introduce the virus to the bloodstream, go to different target organs.
Discovery of hcv in the blood supply:
Lots of cases of hepatitis where they were sure that the patient was not exposed to hepatitis A or B (so they were
called non A non B hep) there was a transmissible agent tht was causing this
Known that if you take this transmissive infectious agent from human blood and give it to a chimpanzee, they
would also get hepatitis (the only other animals that would get this particular hepatitis) they knew that the virus
was in the liver (target organ for this virus)
Isolate the geome ▯identify the virus. Made a dna library; of affected chimpanzees
Made a million clones and arrayed these clones on plates using bacteriophage that would express the protein. U got
all the proteins expressed in the infected chimp’s liver arrayed on plates. Then you can take antibodies from a person you know has nonA nonB hepatitis and you can screen those antibodies to find the places where the
person’s antibodies stick to those particular proteins of ur library. Question
Found fragments of clone DNA that coded for nonchimpanzee proteins. Clones that were attributing to non A non
B hept and when they sequened it,