Manipulating the genes of a virus

[Docscientist]

Genetic engineering can be very helpful in obtaining organisms with desired traits.If that is the case,Why can't we modify the genes of virus and make it more lovable organisms?.I mean what if they are manipulated in such a way that they don't need a host or even if they do,they should be useful to human body like how certain microbes such as lactobacillus,after entering our body,can help us in absorption of food and prevention of unwanted bowel movements.

 

[Drakkith]

I mean what if they are manipulated in such a way that they don't need a host or even if they do,they should be useful to human body like how certain microbes such as lactobacillus,after entering our body,can help us...

That is exceptionally difficult to do. Viruses are extremely simple compared to a cell and therefore are much more limited in what they can do. They have little to no "machinery" like cells do and their entire purpose is to simply carry and pass on their genes in the simplest manner possible. Genetically engineering them to live outside of a host is essentially impossible for these reasons. You'd have to build an entirely different organism. Altering them to benefit the body is much easier, but the possibilities are still limited. Other than serving as a means to insert synthetic DNA into host cells, there just isn't much they can do.

If anyone knows of other possibilities, feel free to post.

,can help us in absorption of food and prevention of unwanted bowel movements.

Well, if you're having problems with the latter, we already have other options.

 

[jim mcnamara]

This is a simplified answer:
Generally, when a virus attacks a cell, it takes over the cells and 'makes' it create lots of virus particles inside the cell. The cell dies, lots of virus particles are freed to infect lots of other cells.

Virus DNA can be modified using CRISPR technology. But if those modified viruses are put in a host and do their thing, you still wind up with more virus particles and dead cells. I do not get what this would accomplish. Maybe you could create safer vaccines this way.

A positive variation that comes to mind: bacteriophages. These viruses attack species of bacteria.
I do not know how practical it is to use 'specially DNA formulated' bacteriophages to kill off pathogenic bacteria in severely ill people, however.

Another issue is the fact that viral DNA can become incorporated into the DNA of mammalian cells. Humans are mammals. So if we do use virus infections to cure another disease do we want some of that DNA to end up in our DNA? How often does this happen?
I do not know.

A decent article you can read without being an expert - note that it claims about 8% of human DNA originated from viruses and mostly it no longer functions; it is more like baggage:
http://blogs.discovermagazine.com/loom/2012/02/14/mammals-made-by-viruses/#.VxJI7XriPIA

 

[Docscientist]

Virus DNA can be modified using CRISPR technology. But if those modified viruses are put in a host and do their thing, you still wind up with more virus particles and dead cells. I do not get what this would accomplish.

You still dwelve around the technology that exists now and that cannot accomplish what I said.We can make a mouse glow at night by inserting in it a DNA of jelly fish.Our biotechnology can do that.But if that is possible,it should be possible to manipulate the gene of virus by inserting in it desired trait like that of lacto bacillus and make it self replicate within our body using DNA polymerase enzyme.So even if too many of them grow in our body since they are modified,they would not cause any damage to the body.In fact,human body has cells that are composed of 90 percent good bacteria.As long as the virus does not possesses any harmful effect against us,it's presence in the body would be to some extent useful if we incorporate few desired traits such as helping our cells in replication,digestion etc...I'm talking about totally modifying the virus and make it ineffective and more lovable towards humans.
If our biotechnology can do that,it would end the struggle between humans and virus and the deaths of millions of poors who are affected by something that they don't even know about.

 

[Ygggdrasil]

Making a free living virus is probably a long ways off and it's not clear why one would start with a virus rather than a bacterium. We don't understand the genes that enable bacteria to be freely living, so creating a freely living virus is a long ways off. It would be possible to try to engineer commensal bacteria to perform beneficial tasks, and research in this area is ongoing. However, a big problem in this area is that the engineered beneficial bacteria (or viruses) usually are not as fit as the microbiota already present in the body, so they are likely to be outcompeted and disappear from the population.

That said, there are a number of biomedical applications for engineered viruses. Viruses can be used for delivery of new genes into the body for gene therapy applications, and would likely be required for using technologies such as CRISPR to edit genes in adult humans. For example, viruses are used in CAR T-Cell therapies, in which doctors genetically rewire one's own immune cells to attack tumor cells.

 

[Drakkith]

You still dwelve around the technology that exists now and that cannot accomplish what I said.

Of course he does. Future technology is unknown to us here in the present and cannot lead to a meaningful discussion precisely because we don't know what will be possible in the future. If you don't want to discuss current science and technology and its relation to the topic then I will have to lock this thread. An exception would be a discussion on cutting-edge technology that has yet to be brought into mass use or technology that we are confident we will have in the near future. But if you want to discuss those then we'd need specific examples, not a vague statement about what "should" be possible in the future with nothing to back it up.

We can make a mouse glow at night by inserting in it a DNA of jelly fish.Our biotechnology can do that.But if that is possible,it should be possible to manipulate the gene of virus by inserting in it desired trait like that of lacto bacillus and make it self replicate within our body using DNA polymerase enzyme.

Note what I said in my first post about viruses not having the molecular machinery that cells have, such as ribosomes, mitochondria, etc. You would have to create an entirely new organism with the required machinery to do anything other than just replicate itself at the expense of the cell. The reason we can make a mouse fluoresce is because a mouse cell already has all the components required to produce the specific fluorescent protein. All it needed was the instructions on how to build it. It's like giving a car factory the instructions for producing a different hood to a car using the machinery they already possess. Doing the same thing for a virus would be like trying to make a call center produce car engines. You'd have to essentially build an entire factory from the ground up. Which would then no longer be a call center.

I agree with Ygggdrasil in that modifying a bacterium for all of this would be much easier than a virus.

So even if too many of them grow in our body since they are modified,they would not cause any damage to the body.In fact,human body has cells that are composed of 90 percent good bacteria.

While the latter fact is true, these bacteria are MUCH smaller than our own cells and mostly occupy our digestive tract and a few other spots as I understand it. So the human body's own cells still make up the overwhelming majority of our biomass. In addition, these bacteria do not replicate by infecting our own cells.

As long as the virus does not possesses any harmful effect against us,it's presence in the body would be to some extent useful if we incorporate few desired traits such as helping our cells in replication,digestion etc...I'm talking about totally modifying the virus and make it ineffective and more lovable towards humans.

Well, what does "Ineffective and more lovable" even mean? I'm looking for specific details here, not just a, "Well, they wouldn't hurt us" kind of answer. I mean specific traits, functions, roles, etc. Otherwise we're all just talking about some vague concept that isn't well defined.

If our biotechnology can do that,it would end the struggle between humans and virus and the deaths of millions of poors who are affected by something that they don't even know about.

No it wouldn't. There's a difference between modifying a virus to be beneficial compared to modifying every virus everywhere to be beneficial, which essentially means that we've eradicated the original species. And that is an entirely different topic and a goal that is essentially impossible. The only human virus we've ever managed to eradicate is smallpox, due in large part to the fact that it has no natural non-human hosts.

 

[jim mcnamara]

In fact,human body has cells that are composed of 90 percent good bacteria.

@Docsc
Hmm. Can you provide a decent citation for this? If this has some merit I'd be interested to say the least.

 

[Ygggdrasil]

Can you provide a decent citation for this? If this has some merit I'd be interested to say the least.

This is a number a lot of people used to cite (you can get to it by a simple back of the envelope calculation), but just a few months ago a paper came out saying the number is closer to 1:1
http://www.sciencedirect.com/science/article/pii/S0092867416000532

It is often presented as common knowledge that, in the human body, bacteria outnumber human cells by a ratio of at least 10:1. Revisiting the question, we find that the ratio is much closer to 1:1.

See also:
http://www.nature.com/news/scientis...s-have-more-bacteria-than-human-cells-1.19136
http://biorxiv.org/content/early/2016/01/06/036103

 

[jim mcnamara]

Thanks. I thought the OP meant something different - number of human cells with bacteria in them. For some reason I didn't think he meant gut bacteria.

But. The Sender et al paper is also news to me. Glad to read it.

 

[Drakkith]

I thought the OP meant something different - number of human cells with bacteria in them.

Gah! That's a terrifying thought!

 

[Fervent Freyja]

Gah! That's a terrifying thought!

You never know, this passionate lady from Princeton might burst your bubble and have you falling in love with bacteria!

Some of the transcript: "There is about a trillion human cells that make each one of us who we are and able to do all the things that we do, but you have 10 trillion bacterial cells in you or on you at any moment in your life. So, 10 times more bacterial cells than human cells on a human being. And of course it's the DNA that counts, so here's all the A, T, Gs and Cs that make up your genetic code, and give you all your charming characteristics. You have about 30,000 genes. Well it turns out you have 100 times more bacterial genes playing a role in you or on you all of your life. At the best, you're 10 percent human, but more likely about one percent human, depending on which of these metrics you like. I know you think of yourself as human beings, but I think of you as 90 or 99 percent bacterial."

 

[Phil Core]

Loved the summation on the number of cells in the human body and the division between actual human and bacteria. I kind of knew this but it is good to see confirmation every now and then.

I did follow the link above and got

"Bonnie Bassler discovered that bacteria "talk" to each other, using a chemical language that let's them coordinate defense and mount attacks. The find has stunning implications for medicine, industry -- and our understanding of ourselves."

I did not follow her talk.

Is it direct chemical change which would necessitate touch or are cells effecting the ph of the medium they are in and thus able to communicate without actually touching?

 

[dlgoff]

Since this thread is still alive and since I couldn't find a good place to post a link to this excellent PBS TV program:

The Gene: An Intimate History” brings vividly to life the story of today's revolution in medical science through present-day tales of patients and doctors at the forefront of the search for genetic treatments, interwoven with a compelling history of the discoveries that made this possible and the ethical challenges ...

Edit: to mentors; please move if there's a better place for this post. Thanks

 

[phyzguy]

Genetic engineering can be very helpful in obtaining organisms with desired traits.If that is the case,Why can't we modify the genes of virus and make it more lovable organisms?.I mean what if they are manipulated in such a way that they don't need a host or even if they do,they should be useful to human body like how certain microbes such as lactobacillus,after entering our body,can help us in absorption of food and prevention of unwanted bowel movements.

Suppose you could modify the genes of a virus to make it harmless or beneficial. You then have a modified virus in your lab. You have not changed the genes of the enormous number of SARS-COV-2 viruses that are multiplying in their human hosts. So you may have created a new virus, but the old, harmful viruses are still out there.

 

[BillTre]

Suppose you could modify the genes of a virus to make it harmless or beneficial. You then have a modified virus in your lab. You have not changed the genes of the enormous number of SARS-COV-2 viruses that are multiplying in their human hosts. So you may have created a new virus, but the old, harmful viruses are still out there.

In addition, the new virus, to have any effect on the presence of the original virus, would have to out-compete the original virus in its reproductive nitch (the human body) in order to displace it.
This would mean releasing the "not so bad" virus to compete over human bodies to reproduce in.
Seem unlikely to me.

There are cases where vectors that spread diseases (like mosquitoes) have been genetically modified and released into the wild (like suburbs). To have any effect on the existing population, the modified genomes usually have some kind of genetic trick to drive the modified genome to spread through the population. Without, that the genetic modification would remain a small proportion of the population or possibly a small and shrinking part of the population because it might no longer be as well adapted to its environment.

 

[Laroxe]

I think as a starting point we need to consider that viruses are parasites and as a general rule their prey do not want to share their resources or die simply for them to reproduce. Most of the viruses that exist are unclassified and unstudied but as far as we know, none exist with the intention of helping their prey. Its true that we can use viruses but this is usually to either kill something else we don't like or to use their ability to penetrate into a cell to insert specific genetic material, these viruses are then required to die as their reproduction would kill the cell.

I would also question the idea that the bacteria that use us as their home do so with the intention of being useful, yes they can protect us from some infections, but that is really them protecting their home from interlopers. Most of these bacteria are confined to very specific and usually external surfaces of our body (this includes the gut) and our own immune system only tolerates them in these specific areas. Many of these same bacteria if they gain entry to our body are in fact dangerous pathogens. Phages that are studied in this population simply represent the diseases that they have to deal with. Something that is rarely reported in the studies of the human biome is that in animals, raised in a totally sterile environment have a longer lifespan than those with their natural biome's