Regulation of Transposable Elements - Video Tutorials & Practice Problems
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Hi in this video we're gonna be talking about regulation of transportable elements. So regulation of these transposon movement is really not well understood. Scientists don't have a good grass on how these are moving. What causes them to move? What causes them to not move. Um But there has been some research into non coding RNA. S. That can silence and stop the transpose on movement. So remember some examples of non coding RNA. Those are things like S. I. R. N. A. S. Micro RNA pi R. N. A. S. There's all these different types of non coding RNA. S. And some of them we found that our scientists have found that they affect transpose on movement or can. So the first example of this is actually the TC one transpose on and see elegance. Remember C. Elegans are those words C. Three worms and the T. C. Transpose in is found in the genome meaning that it's going to be found in somatic cells. So the cells that make up the worm body and the worm neurons and all of that. And also the worm germ cells, the worm eggs essentially. But the transpose on actually only jumps around in the store Matic cells in the germ cells it doesn't it's completely stationary. And so scientists were like well it's present in the germ cells so why isn't it moving? And so what they found is that in the germ cells this TC one transpose isn't is actually transcribed. So it's transcribed normally as part of another gene. So this gene is being transcribed and it's kind of found at the end of that gene but that RNA plagiarized it keeps going. It keeps transcribing and it eventually transcribes the TC one. Then you have to see one RNA. And this T. C. R. N. A. T. C. One RNA contains a repeated sequence. Like most of these transfusions have those repeated sequences at the end and those repeated sequences actually because it's now transcribed as a single strand RNA A. Right that causes that are in a two fold upon itself and bind those repeated sequences that are really similar. And when it folds upon itself it becomes D. S. R. N. A. Now do you remember does the cell like Ds RNA does it just sort of allow it to sit there in the cell and just be like oh you're fine. You know you're a little abnormal but we're just gonna allow you to sit here. No. Right? The cell is like oh my gosh there's double stranded RNA. I gotta get rid of that immediately. And so it does. And so it activates the sort of RNA interference pathway that we've talked about with. Micro RNA. S. And S. I. R. N. A. S. So the cell recognizes double stranded RNA. And it brings in dicer which if you remember we talked about that, we may have talked about that in the RNA interference. But if you're not familiar with it your book maybe a little bit out of order. But essentially there's this protein it comes in it recognizes double stranded RNA. A. And it's called dicer. So it processes it and then the second protein comes in called risk and that binds to it. And um when our risk binds to this process TC one transpose on it then targets it to degrade other TC one transcript. So what happens the TC one gets transcribed. The RNA folds on itself. That sounds like whoa there's double stranded are brings in dicer brings in risk. And when T. C. One is bound to risk that targets it to degrade other TC one transcripts. So that means that those transpose sins are never getting their number jumping because whenever they get transcribed they're immediately destroyed by this risk TC one complex. So what happens is you have a gene and very close after you have this transpose on. So when the protein comes on to bind to transcribe what you get is you get the gene RNA and you also get the T. C. One RNA. This PCR one RNA has inverted repeats that folds upon itself when it folds upon itself that's targeted by dicer and risk and risk binds to it after its process and targets these transcripts for degradation. So these these and all the rest of them will be degraded. And so this is an example of how non coding RNA. S. Will work to degrade these transpose sins and suppress their movement. So some examples of other um elements that help regulate transposes scenes are pi R. N. A. And this is an example in other animals and this works very similar to the to the method we talked about above. But I do just want to mention some of the differences. So the first is that pipe clusters exist and pi clusters are huge regions of DNA that contain the transpose eons. And these transpose er just transcribed as these large pieces of D. N. A. So these trains they have this long long long, long, long. I mean huge transcript. Right? The RNA transcripts are processed and when they're processed their complex with the protein this protein names Argonaut, you don't necessarily need to know it but I'm just here in case you're interested in what the proteins name is. But essentially you have this long RNA. It's processed into little transpose seasons. These come in they bind to Argonaut and when they're bound to Argonaut that goes around and degrades all the other transcripts. Again very similar to how this works above. Just sort of different names. The pie clusters and the Argonauts are the different names of how this works. There are ways that this works in bacteria through Cr. R. Day and um this is very similar. I'm not going to go through the process again. But essentially this process or the the mechanism through which it works is called crisper which you may actually have heard of. I think there may be potentially making. A show about crisper and then gene editing. Um I got a big network or something, I'm not really sure. But anyways you may have heard of CRISPR. It's kind of this big new hit thing in science for gene editing. But essentially it works by targeting different genes for silencing and degradation and it does so by targeting transpose sins as well. So like I said scientists aren't sure if this is the only way that transpose are regulated. They could be regulated in a number of different ways that scientists don't know about yet. But essentially they think that the non coding RNA is at least one major way that transposes scenes can be silence in cells in which they're not expressed. So with that let's not move on.
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Problem
Problem
Which of the following molecules are known to be able to regulate transposon movement?
A
DNA
B
RNA
C
Protein
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Problem
Problem
Which type of RNA is known to regulate transposon movement in C. elegans?
A
Tc1 RNA
B
piRNA
C
miRNA
D
crRNA
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