Thread: Retroviruses and Prokaryotic Cells

I have a question; would prokaryotic cells (cells without a nucleic membrane or a nucleus to contain the DNA stored in the cell) be more susceptible to retroviruses? Or do they not affect prokaryotic DNA as (as far as I know) it is a different shape (circular, if I recall correctly) than that of a eukaryotic cell? (Which has DNA as a double helix, with thymine, guanine, adenine, cytosine, and two "phosphodiester backbones".)

My "theory" is that since there is no nucleic membrane or nucleus to protect the DNA, it is more easily accessible to the retroviruses. If this is not true, then what about adenoviruses?

One thing I have learned about people on this forum is that no matter how nonsensical someone's "theory" is, you will try to correct them. I thank you for your time.

The nuclear membrane does not protect cells from retroviral infection, or from viruses that replicate within the nucleus or cytoplasm. The cell wall of bacteria would seemingly pose a far more formidable barrier to infection, yet it is easily overcome by bacterial viruses.


The defining characteristic of retroviruses is their ability to convert their RNA genomes in to DNA - the enzymatic process of reverse transcription. Like eukaryotes, bacteria can also suffer from viral infections wherein the virus integrates its own genome stably in to that of its host. A classic example would be bacteriophage lambda of E. coli. These viruses may exist in an integrated state for 10's, 100's or 1,000's of generations before "deciding" to activate and then ultimately destroy their host cell.


I would rephrase your question as: Why is the process of reverse transcription not a feature of viruses that infect bacteria? I have no answer to that.


For some reason or another, there are very few RNA viruses that infect bacteria. Retroviruses themselves seem to be pretty much restricted to vertebrate hosts. Plants can be infected by retroviral-like viruses (the pararetroviruses), but these, unlike retroviruses, have DNA genomes.

Thank you; I guess there's no need for this thread anymore.

Sorry! Just to quickly add something (I know that Zwirko already answered your question!)

The reason why the retroviruses we have studied thus far do not affect bacteria is because these viruses make use of certain membrane proteins that allow adhesion and injection into the cell. This is not to say that there are no retroviruses that attack bacteria, just that I have not heard of anyone having discovered a bacteriophage that exhibits reverse transcriptase activity (it could totally exist though, there are an estimated 10^30 different types of bacteriophage.... anything is possible with those kinds of stats)