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hepatitis B virus?

Ashok Aiyar aiyar at ebv.oncology.wisc.edu
Mon Nov 11 12:14:50 EST 1996

On 10 Nov 1996 05:05:52 GMT, hbkg at hitel.kol.co.kr <hbkg at hitel.kol.co.kr> wrote:
>Curious to know whether or not HBV replicates from RNA via DNA to RNA?
>Does it go through DNA forms like HIV virus?

It is more accurate to say that HBV replicates from DNA to DNA via 
an RNA intermediate (i.e DNA via RNA to DNA).  Like HIV (and other 
retroviruses) this involves reverse transcription.  The mechanisms
evolved by HBV to generate a circular duplex DNA copy of the single
plus strand genomic RNA is quite different than the mechanisms used
by retroviruses to generate a DNA copy of their dimeric RNA genome.

Unlike retroviruses, HBV appears not to have evolved a specific
mechanism to integrate it's DNA into the host.  In HBV associated
hepatocellular carcinomas, the viral DNA is frequently found 
integrated into chromosomal DNA.  The mechanism of this integration
is unknown, but is likely to involve rolling circle replication, as
there are usually multiple copies of the viral DNA juxtaposed in
series in such integrations.

Curiously in some mammalian hepatitis B viruses (eg. woodchuck
hepatitis virus) integrations at or near the N-myc2 locus are
frequently observed in WHV associated hepatocellular carcinomas.

[follow-ups redirected to bionet.virology]
Ashok Aiyar, Ph.D.
Department of Oncology            email: aiyar at ebv.oncology.wisc.edu
University of Wisconsin-Madison                  tel: (608) 262-6697

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