Lysogenic Conversion

[Axon hillock]

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I was just wondering about this one topic. In a lysogenic infection can the viral DNA, which is inserted into the host genome, code for some type of toxin which can kill the host cell? The Grad student at my research gave me a very confusing answer and I just want to see what other people think.
-Thanks

 

[Axon hillock]

Anyone?

 

[MD Odyssey]

Anyone?

Thinking. Unfortunately, I'm not a biologist.

 

[MT Headed]

I wrote a smart@ss answer to this question last night, but I never posted it because I figured I would wait for the experts to chime in. Anyway, here is what I thought about posting:

Manufactured viruses? Sure, why not? You may stumbled upon the cure for cancer. Some forms of cancer interfere with the cell's natural apoptosis mechanisms, after all.

Natural viruses? This plan does not lend itself to generating additional virions to spread the virus, so it seems that viruses like these would not last more than one viral "generation".

 

[Axon hillock]

I wrote a smart@ss answer to this question last night, but I never posted it because I figured I would wait for the experts to chime in. Anyway, here is what I thought about posting:

Manufactured viruses? Sure, why not? You may stumbled upon the cure for cancer. Some forms of cancer interfere with the cell's natural apoptosis mechanisms, after all.

Natural viruses? This plan does not lend itself to generating additional virions to spread the virus, so it seems that viruses like these would not last more than one viral "generation".

That would be interesting. Anyway, if a virus like this was manufactured then i feel that there must be an example of it in nature. Most of our medical/scientific breakthroughs come from observing nature. It's an interesting viewpoint which I didn't consider. Let's see what other people think.

 

[km1865]

Well if a lysogenic virus produced a toxin to KILL the cell, I think it would no longer be lysogenic and would probably be considered lytic at that point, since the definition of a lytic virus is that it KILLS the cell in the infection process. And of course, you can have certain factors that cause the lysogenic virus to become virulent (lytic) like exposure to radiation, stress etc..

 

[Axon hillock]

Well if a lysogenic virus produced a toxin to KILL the cell, I think it would no longer be lysogenic and would probably be considered lytic at that point, since the definition of a lytic virus is that it KILLS the cell in the infection process. And of course, you can have certain factors that cause the lysogenic virus to become virulent (lytic) like exposure to radiation, stress etc..

Lytic cycle is completely separate topic and your missing the point of my question. We know that when a lysogenic virus incorporates its DNA into the host genome it can result in the change of the host cells phenotype. My question is basically can the incorporated DNA produce a toxin which kills the host cell.

 

[Kalamazoo]

Lytic cycle is completely separate topic and your missing the point of my question. We know that when a lysogenic virus incorporates its DNA into the host genome it can result in the change of the host cells phenotype. My question is basically can the incorporated DNA produce a toxin which kills the host cell.

It definitely seems possible, but not likely since a virus utilizes host cells for their reproduction. If it tends to kill a host, it would end up finding a more suitable host cell so that it can actually reproduce.

 

[mohad]

nevermind.

 

[Axon hillock]

So any more opinions? Who else thinks that a toxin can be produced during the lysogenic cycle?

 

[whiteshadodw]

So any more opinions? Who else thinks that a toxin can be produced during the lysogenic cycle?

I think this question is too detailed and you're looking for too detailed of a response.

If you want to get into the nitty gritty, then isn't CO2 gas, a natural byproduct of the Krebs cycle, toxic to the cell or the body? Ketone bodies as a result of beta-oxidation are also a natural byproduct and can be 'toxic' to cells. It doesn't kill them, but it does put them under stress. A toxin doesn't necessarily have to kill a cell.

With that said, I think that a virus in a lysogenic cycle can produce toxins. There's tons of cancer causing viruses that don't ever go through a lytic cycle. In fact, there are some viruses that don't even go through a 'lytic cycle' and still produce more virion particles (HPV). So its certainly possible to have a virus that's toxic. Moreover, look at some of the mechanisms of these viruses. Some of them at mutagens and they induce ridiculous amounts of error during replication. If that doesn't count as being toxic, then I don't know what does.

Also, if you're super curious, T4 lambda phage is one of the most studied viruses. The mechanisms of the lytic and lysogenic cycle are very well understood for T4. You'll see that in order to maintain lysogeny, the virus can't just integrate its DNA and have the rest of its viral proteins disappear. The viral proteins have to hang around in case virus 'wants' to go through a lytic cycle.