Transposons | Transposable elements | Types of transposons| how transposons work?

hello in this video we'll talk about transposons which are dna sequences that can move from one location in the genome to another and that's why they are known as jumping genes the pioneering work on transposon came from barbara mclintock and for her work she was recognized and awarded the nobel prize in 1983. let us look at how transposons work transposons can work in two different operational modes in first mode they can jump from one location in the genome to the another location and in this process they don't leave any copy behind this is known as non-replicative mode of transposition in the second regime they can make a copy of themselves and that copy can jump from one location to another this is known as replicative mode of transposition so we can understand there are two modes of transposition first is without duplication and the second is with duplication you can imagine these things to be a cut and paste and copy and paste mechanism i know you can relate that interesting fact is transposable elements composes 50 percent of our genomes but they are generally epigenetically silent now the question is what are the function of these transposable elements how they are relevant for us or our physiology it turns out that transposable elements are involved in several diseases like myocardial infarction neurodevelopmental disorders neurodegenerative diseases and even it has neuro it has immune modulatory functions that means transposable elements are fairly important but the question is how do they work so let's try to understand that part in a moment now the jump the jumping genes can jump from one location to another but the biggest question is what's the big deal about it yes there is a big deal behind this jumping process let's say a transposon jumps from one location in the gene and lands inside a coding sequence of a structural gene that means it would disrupt that particular gene right now this particular gene has an open reading frame and this open reading frame is now disrupted due to the integration of transposon that means possibly the functional product of that gene would not be obtained there could be other consequences of this transposition let's say a transposon hops and lands into a regulatory sequence inside a genome now this regulatory sequence controls the transcription right so obviously after integration into a regulatory sequence it can positively or let's say negatively regulate gene expression from a nearby gene so obviously transposon has activity on on gene expression as well so let's summarize this part transposon can show mutagenic effect they can get inserted into a location and disrupt a gene they could silence nearby genes by attracting epigenetic modifiers transposons can also act as a source of long non-coding rna and thereby they have great regulatory roles and lastly they can act as enhancer or repressor and thereby controls gene expression as well now let's talk about the classification of transposons at least the overview of it transposons can be divided into three broad classes dna transposons virus-like retrotransposons and poly-a retrotransposons each of them has their distinct features let's talk about dna transposon first which has a particular region known as transposes coding region which codes for the transposes enzyme now apart from that the other feature is the terminal inverted repeats which is recognized by the transposes so let's see how they work so the transposes enzyme recognize the inverted repeats in the terminals and they cleave the dna and creates a double-stranded dna break now these transposable element can be integrated to a new region in the genome and thereby it can jump from one location to another so this is how the integration works now let's talk about the virus like retrotransposons these has inverted terminal repeats as usual but at the same time it has two genes encoding for reverse transcriptase and integrase and both of these are important for the function of virus like retrotransposon let us try to understand that so let's try to understand how virus like retro transposons get integrated into the genome so first the transposon would be transcribed and reverse transcriptase would make a copy of that and forming a cdna-like structure so this cdna or the cdna intermediate would be integrated into a new location with the help of the enzyme in degrees and thereby the virus like retrotransposons get into a new genomic location let's talk about poly a retrotransposons which exactly look like a gene why is so let me tell you so these retrotransposons differ from other classes of transposons by not having the inverted terminal repeats they have five prime and three prime utr just like our mrnas they also have two orfs or f1 and two and lastly they have a at rich region which mimics the polyetail of an mrna so they pretty much look like a gene now the orf1 encodes for a rna binding protein and orf2 encodes for a protein which has endonuclease and reverse transcriptase activity now exactly how it why the how poly a like retrotransposon work it's beyond the scope of this overview video in a different video i will be discussing how these particular retrotransposons work now let us try to understand more applications of these transpose transposons transposons are really important in the field of molecular biology especially the recombinant dna technology let's say you want to create a stable transgenic cell line so obviously your transgenic construct need to be integrated into the genome and that is done by piggyback vectors which are actually transposon based vectors so this piggyback vector along with the transposes enzyme is injected into the cell and the cargo is integrated with the help of transposition mechanism and this integration is fairly stable so obviously let's say this cargo is a gfp so you can create a cell line which is stably expressing gfp now principles of transposition is nowadays used in atac sequencing or attack sequencing and this particular sequencing technique is used to study chromatin accessibility so especially in terms of molecular biology the principles of transposition is fairly important now let us quickly summarize what we have learned so far we have learned what are transposons how do they work what why transposons are important their implication in disease and biomedical sciences and lastly we also learned about different classes of transposition transposons so this was a overview video in subsequent video we'll delve into deep of all of these uh transposon classes and how they function their examples and their relevance thanks for watching if you like this video give it a big thumbs up don't forget to like share and subscribe thank you

Channel: Animated biology With arpan

Views: 119,073

Keywords: transposable elements, transposon, transposons, is elements, insertion sequence, jumping gene, transposons jumping genes, retrotransposon, genetics, issr, ssr, ac ds elements, tn, molecular biology, transposable element, transposons in eukaryotes, transposons in prokaryotes, transposons in bacteria, transposition, Arpan parichha, jumping genes, transposable elements in prokaryotes, retroviral transposons, non retroviral retrotransposon, transposase, csir net, csir net 2021

Id: VLRksFGhboo

Length: 8min 21sec (501 seconds)

Published: Sat Jan 01 2022