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iceyed913 t1_irav3hd wrote

Reply to comment by Tim_the_geek in How come some viruses lasts years? by alttoupvotemyself

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

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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?

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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.

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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.

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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

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