Using animal models of human diseases can lead to insights into t...

Question

Using animal models of human diseases can lead to insights into the cellular and genetic bases of the diseases. Duchenne muscular dystrophy (DMD) is the consequence of an X-linked recessive allele.

How would you make a mouse model of DMD?

Accepted Answer

Hi everyone. Here's our next problem. Which of the following methods is commonly used for introducing a mutated D MD gene into mouse embryos to create AD MD mouse model in terms of efficiency and specificity. Choice. A pronuclear injection B CRISPR has nine mediated gene editing C lent vial mediated gene transfer or D retroviral mediated gene transfer. Uh First of all, just to note that ad MD mouse model would be a mouse model for Duchenne muscular dystrophy. So you're introducing a gene for the same gene mutation that occurs this, that causes this condition. And our question is asking us to focus on a commonly used method noting that it is used because of its efficiency and specificity. So we want to think about those qualifications when looking at the different methods. Well, our answer is going to be choice B CRISPR cas nine is the technique used to introduce this mutated gene because it does have high efficiency and specificity. It uses guided MRN A to target the gene very directly and then cuts out that specific gene and replaces it with a mutated gene since it's based on a DNA repair mechanism. When we look at our other answer choices. Um Choice. A pronuclear injection was a really common way of generating transgenic mouse lines um developed as early as the 19 eighties. It's been around for a long time, but it has very low efficiency. So it involves directly uh injecting the gene you want into the zygotes but has extremely low uptake. So compared to CRISPR cas nine, the efficiency rate is much lower. So that's why choice A is not correct C and D are related because see lent vial mediated gene transfer. Um A lent virus is a retrovirus. So, ltro viral mediated gene transfer is a form of retroviral mediated transfer. So they share many of the same um benefits and drawbacks. And these are widely used uh methods of gene editing because retroviruses uh incorporate their DNA into the host DNA. So for instance, the HIV virus uh does this, they have RN A based genomes that RN A gets transcribed and directly incorporated into the host DNA? The advantages of this are, it's quite efficient. Uh disadvantages are you could have an immune system response. You can have um duplicate incorporations into the host genome. And you could also perhaps most seriously incorporate near oncogenes which obviously carries a risk of cancer with this technique also because they permanently incorporate their DNA into the host that can obviously be undesired in that uh you might not want that DNA there permanently CRISPR CAS nine, you're editing specific genes you're not permanently incorporating a gene into the person's genome. So that's why choice D is not our answer. Then lent vial, obviously similar disadvantages. Why LRO viruses are used specifically is that they can um unlike general retroviruses, they can incorporate or in fact, I should say um into nondividing cells, unlike other retroviruses. So that obviously makes them um more useful in terms of a wider ability to use them. But again, they have the same drawbacks and they are lacking specificity. Uh since they don't have that guided uh the guiding our MRN A, guiding them, just a specific gene, they can incorporate in a lot of different places and have sort of non um non desired side effects. So that's why choice C is not our answer. So again, the model commonly used for introducing a mutated D MD gene into mouse embryos choice B CRISPR cas nine mediated gene editing. See you on the next video.

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Using animal models of human diseases can lead to insights into the cellular and genetic bases of the diseases. Duchenne muscular dystrophy (DMD) is the consequence of an X-linked recessive allele. How would you make a mouse model of DMD?