Submitted by alttoupvotemyself t3_xwzpm8 in askscience
iceyed913 t1_ir9hkx1 wrote
cause they integrate into your dna via reverse mrna transciptase. this is only a concern with specific viruses types and only when you get older and immune system gets weaker. thinking of aids or herpes family viruses here. edit: also stress due to exhaustion will deplete your natural dna restoration mechanisms and immunity against cells showing abberant behavior, so then you get flare ups causing pathological damage to tissues
The_RealKeyserSoze t1_irbouty wrote
Just to clarify Herpesviruses are not retroviruses and most herpes viruses don’t integrate with the host genome (the few that do use a completely different mechanism than HIV). Herpes tends to hide out in cells that are left alone by the immune system allowing for chronic infection.
Tim_the_geek t1_iraky47 wrote
I thought mRNA doesn't affect/change your DNA. Can you explain the mechanism?
iceyed913 t1_irav3hd wrote
mrna transcriptase makes dna into mrna. reverse transcriptase makes mrna into dna. this gets laced into the nucleus dna via a few other enzymes. im a bit rusty on the specifics but there are a few mechanisms through which this proces can take place throughout all organic life. its how bacteria exchange antibiotic resistance genes and such
Tim_the_geek t1_irbeebl wrote
What is required for reverse transcriptase? mRNA, and enzyme and a cell? How long is the new genetic code part of that DNA? Forever?
The_RealKeyserSoze t1_irbmwgs wrote
Reverse transcriptase is a viral enzyme. Normally you cant go RNA-> DNA. Retroviruses use it, there are only two retroviruses known to infect humans: HIV and HTLV. Both of those viruses manage to keep their genes integrated in at least some cells forever, which is why curing HIV is very difficult despite effective treatments that prevent viral replication.
However other viruses that cause persitent infection do not use reverse transcriptase. Some (like HPV) can integrate with the genome but they are DNA viruses integrating with DNA (and not retroviruses). Herpes viruses generally dont integrate with the genome but a few can (again DNA to DNA), but chickenpox (a herpesvirus) as well as herpes simplex (the one you probably think of when you think of herpes) infect nerve cells and hide out in them as the immune system usually does not attack nerves, so they persist through a completely different mechanism from genome integration.
[deleted] t1_irbobyb wrote
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B_r_a_n_d_o_n t1_irc7kp9 wrote
>> How long is the new genetic code part of that DNA? Forever?
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Yes, forever.
We have quite a lot of DNA injected into our cells from viruses in the distant past.
[deleted] t1_ircolu2 wrote
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iceyed913 t1_irbi402 wrote
im pretty sure there is an error correction mechanism that removes genetic sequences which seem out of place or mutations. no idea how likely it is to always work, but infected cells are cleaned up through autophagy, programmed apoptosis (this is like murder and suicide), so viral sequences will most likely be removed at some point. chronic viral infections like aids and herpes are forever though. edit: i do not have a degree or anything in this area, so if you want to know more im sure youtube has simple videos explaining these things
Agood10 t1_irde2ek wrote
Herpes isn’t a retrovirus. Nor is HPV, per OP’s specific example.
HIV and HTLV are the only circulating retroviruses known to integrate into the human genome. The only example of a non-retrovirus integrating into host DNA that I’m aware of (not to say there aren’t others) is HPV, which can unintentionally become integrated into host DNA due to DNA damage and subsequent repairs that incorporate the viral DNA. This isn’t so much a cause of poor clearance though, at least for HPV, as the integrated DNA isn’t capable of producing viable new HPV virions.
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