DNA Transfer into Cells: Videos & Practice Problems

DNA transfer into cells is crucial for biological studies. Transfection introduces DNA into cultured cells using chemicals, electricity (electroporation), or microinjection. Transduction employs retroviruses to deliver DNA, integrating it into the host genome for stable transformation, ensuring long-term presence during cell division. Transgenic organisms are genetically modified, either by adding transgenes or knocking out genes. This process enhances understanding of gene function and disease mechanisms, making it vital in genetic engineering and biotechnology.

DNA Transfer into Cells

Hi, in this video we're going to be talking about DNA transfer into cells. Often, scientists need to be able to get some type of DNA into cells. Whether they are studying those cells, or they're studying that DNA, or they're studying the mutation, being able to put DNA into cells is super important for being able to study biology. And so, there are a few different ways we can do this. The first we're going to talk about is transfection, which is putting DNA into cultured cells. Those are cells you're growing in a laboratory, usually in some kind of dish, with media on top, things like that. And how you get DNA into these cells, cells being cultured or grown in a laboratory, there are processes that use chemicals. You can use electricity, that's called electroporation, or you can actually just take a little kind of needle and inject it in there. All of these ways will get DNA into cultured cells. So that's transduction. Now we have transduction, and this is actually getting DNA into cells using viruses, it's viral mediated. And what you do here is you take a virus, generally what's used is a retrovirus, remember that's a virus that contains RNA but then it's turned into DNA inside the cell. Usually, you use a retrovirus, and this retrovirus, the scientists have made it perfectly however they want it. So, it's genetically engineered, and it contains the DNA that they want. So, generally, this retrovirus will contain, some of its own DNA, but mostly the DNA that the scientists want to put into the cell. And so, they create the virus that way, so that it contains the DNA of interest instead of its normal viral DNA. Luckily with viruses, they just automatically infect cells. Right? That's what they're meant to do. So you don't have to worry about how you're getting the virus into the cell. Usually, you just introduce the retrovirus that contains the DNA of interest, and put it into wherever the cells of the organism are growing, and then that virus is going to infect, that's what it does best. And when it infects, that DNA gets into the cell. We call this there's a special type, and it's called a stable transformation when the DNA is actually integrated into the host cell genome. So not only is the DNA getting into the cell, which we could have done through chemicals, or electricity, or microinjection, but in stable transduction, these retroviruses have special DNA and special proteins in there for a short period of time, but it's in there for the life of the cell. As long as the cell has its genome, that DNA that you're studying will also be there. And that's a really important technique, that stable transformation, where that DNA stays there for the life cycle of the cell. And then also when the cell divides, right, that it remains in the genome, it gets copied like normal cell division would, and then that gets passed on to all the other progeny cells. So that stable transformation stays in the cell. This one's super important and is a bit stronger than this transfection process because that is the DNA is only going to be in there for a little while. It never gets integrated. Once the cell replicates and divides, it's not passed on, so transduction is a stronger and longer-term process. So we talked about transduction, we talked about transduction. Let's talk about transgenic organisms. Transgenic organisms, they've been genetically altered in some way. So, the DNA of the organism has been changed. This can be through the addition of DNA called a transgene, which can be usually genes from other organisms. So, if you have a transgenic mouse, you maybe would put in a gene from a jellyfish, which is something that people do to make mice glow. It could also be mutated genes or genes with extra parts on them, anything that's different than a normal gene that the organism would have. Those were called transgenes. The other type is a knockout, and that's going to be exactly what it sounds like. It sort of knocks out that gene. It either inactivates it or deletes it. Inactivating it would be something like it puts a mutation, a stop codon really early in the sequence that would potentially inhibit it or inactivate it. Or it can delete it, meaning that it just chops it out altogether, and then that DNA piece is lost for good. So these transgenic organisms, their DNA is being altered either through the addition of genes from other organisms or mutations or whatever, the addition of this DNA or through, the losing this DNA through knockouts. So, this is an example of transduction and stable transformation, so you don't need to know these steps, and you don't need to know this at all either. But essentially, this is the cell that creates the virus that is used in transduction, a stable transformation. So, what happens is you can see all these processes. This is a virus being created, and here we have our virus, and scientists collect this virus, and then they infect the cell that they want to have that DNA. So, the virus gets in, you can see that the RNA, remember this is a retrovirus, so it starts out as RNA, it's changed into DNA, and then that DNA actually goes into the nucleus, and integrates itself into the host cell chromosome, which you can see here in purple. So, transduction is the process of using the virus, transduction, and the stable transformation is the process of making sure that DNA integrates into the host cell genome. So, with that let's move on.

Which of the following methods uses electricity to get DNA into cells?

• A. Transfection
• B. Transduction
• C. Stable Transformation
• D. Transgenic Organism Creation

Answer: (A)

Here’s what students ask on this topic:

What is the difference between transfection and transduction in DNA transfer?

Transfection and transduction are both methods of DNA transfer into cells, but they differ in their mechanisms. Transfection involves introducing DNA into cultured cells using chemicals, electricity (electroporation), or microinjection. This method is typically used for short-term studies as the DNA does not integrate into the host genome. On the other hand, transduction uses viruses, usually retroviruses, to deliver DNA into cells. The viral DNA integrates into the host genome, ensuring stable transformation and long-term presence of the DNA during cell division. This makes transduction more suitable for long-term genetic studies.

How does electroporation work in DNA transfer?

Electroporation is a method of DNA transfer that uses electrical pulses to create temporary pores in the cell membrane. When a high-voltage electric field is applied to cells in the presence of DNA, the cell membrane becomes permeable, allowing the DNA to enter the cell. Once the electrical pulse is removed, the cell membrane reseals, trapping the DNA inside. This technique is effective for a wide range of cell types and is commonly used in molecular biology to introduce plasmids or other genetic material into cells.

What are transgenic organisms and how are they created?

Transgenic organisms are genetically modified organisms whose DNA has been altered through the addition of foreign genes (transgenes) or by knocking out specific genes. To create a transgenic organism, scientists introduce new DNA into the organism's genome using methods like microinjection, electroporation, or viral vectors. The introduced DNA can come from different species and can include genes that confer new traits or functions. For example, a transgenic mouse might carry a gene from a jellyfish to make it glow. This technology is crucial for studying gene function and developing new treatments for diseases.

What is stable transformation in the context of DNA transfer?

Stable transformation refers to the integration of introduced DNA into the host cell's genome, ensuring that the DNA is maintained and passed on during cell division. This is typically achieved through viral-mediated transduction, where retroviruses are used to deliver the DNA into the cell. The viral DNA integrates into the host genome, allowing the introduced genetic material to be replicated along with the host DNA. This method is essential for long-term genetic studies and applications, as the introduced DNA remains in the cell lineage over multiple generations.

What are the applications of transgenic organisms in research and biotechnology?

Transgenic organisms have numerous applications in research and biotechnology. In research, they are used to study gene function, understand disease mechanisms, and develop new treatments. For example, transgenic mice can model human diseases, allowing scientists to study disease progression and test potential therapies. In biotechnology, transgenic organisms are used to produce pharmaceuticals, improve agricultural crops, and develop biofuels. For instance, genetically modified crops can be engineered for pest resistance, increased yield, or enhanced nutritional content, contributing to food security and sustainable agriculture.