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  #1  
Old 01-21-2010
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Virus Virus Replication

There was a question from UWSA which sounds something like :

"Which virus replicates in Human Epithelial Cell's nucleus, and uses host cell enzymes."

The answer was HPV.

But i went and put Togavirus as an answer, reasoning that it is not a -ve stranded virus hence does not bring its own polymerase. (I totally missed the replicate in nucleus part)

But later I realize I was utterly confused with the question, and I have got my virology concepts mixed up.

Is it correct to say that ALL viruses in our USMLE syllabus will always need host cell enzymes to replicate?
The difference is just if they carry an extra enzyme with them or not?
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Old 01-21-2010
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Default DNA Viruses replicate in the nucleus

The issue here is not whether they need the host cell enzymes or not. The question is about "WHERE" do they replicate.
Apart from few exceptions, DNA viruses replicate in the nucleus and RNA viruses replicate in the cytoplasm.
Tell me did that question mention any other DNA virus in the options in addition to HPV?
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Old 01-21-2010
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Nope, you hit it right on Sabio. All the other answers are RNA viruses.

Btw, since Influenza virus and Retrovirus do not replicate in the cytoplasm, is it correct to assume that they replicate in the nucleus, just like other DNA viruses (besides Pox)?
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Old 01-21-2010
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Quote:
Originally Posted by lemontea88 View Post
Nope, you hit it right on Sabio. All the other answers are RNA viruses.

Btw, since Influenza virus and Retrovirus do not replicate in the cytoplasm, is it correct to assume that they replicate in the nucleus, just like other DNA viruses (besides Pox)?
Yes, you are damn right.
All RNA viruses replicate in the cytoplasm except Retrovirus and the segmented Orthomyxo.
All DNA viruses replicate in the nucleus except Pox.
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Old 01-11-2011
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Default

Quote:
Originally Posted by lemontea88 View Post
There was a question from UWSA which sounds something like :

"Which virus replicates in Human Epithelial Cell's nucleus, and uses host cell enzymes."

The answer was HPV.

But i went and put Togavirus as an answer, reasoning that it is not a -ve stranded virus hence does not bring its own polymerase. (I totally missed the replicate in nucleus part)

But later I realize I was utterly confused with the question, and I have got my virology concepts mixed up.

Is it correct to say that ALL viruses in our USMLE syllabus will always need host cell enzymes to replicate?
The difference is just if they carry an extra enzyme with them or not?
actually the discussion is done here ,but regarding the enzymes not the place,consider that it depends on the enzyme type and i think they would not be that picky anyway.btw,if its a dna to rna enzyme,they might rely on the host but in the case of making dna from rna,they have to encode it themselves(HIV and HBV).also pox,the odd of DNA guys,has a DNA dep. RNA polym. which enables him to work in the cytoplasm.

regarding the place,just an extra point,
orthomyxo(influenza) replicates in both the cytoplasm and the nucleus.
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Old 01-11-2011
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Smile

Here's a quick mnemonic:

Pox replicates in the cytobox!
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