in this short video we'll talk about the micro rnas micro rnas are class of non-coding RNA that play important role in regulating gene expression so the major function for micro RNA are involved getting involved in the gene regulation Network so micro rnas are associated with development of an organ let's say brain it is involved in cancer it is also involved in regulation of large Gene networks we'll talk about all of these in this video so first let's see how micro rnas work so there are dedicated genes in our genome for the micro rnas so these Gene doesn't encode a protein but they encode a micro RNA so the first transcript that comes out of these kind of genes are known as primary micro RNA transcript and these primary microorganic transcript get further processed with the help of enzymes known as drosha and dgcr8 or Pasha so the the pre micro RNA transcript gets further trimmed eventually this particular pre-micro RNA transcript would be moving out of the nucleus with the help of the exporting 5 complex as shown here once outside in the cytoplasm it would be assembled with several other proteins known as dicer and dicer further chops off this kind of loop structure at the end and now there are two strands of these micro RNA which would eventually be associated with Argonaut proteins and it will eventually form the risk complex or rnai silencing complex only one strand of these micro RNA would be loaded into the rnai silencing complex it binds to specific region of the MRNA and most of the cases it lead to degradation of the MRNA this is how overall micro RNA can work but there are many aspects to it like the production of microorganic would be way more complicated that we have seen right now so at a simplest level there could be one micro RNA from one particular micro RNA Gene there could be also multiple micro RNA or an array of micro RNA coming out from one Gene and later on they are getting processed there could be also micro RNA as a part of an intron in a protein coding Gene so all these possibilities are there in a live cell question is where does Micro RNA binds micro RNA can possibly bind to different uh untranslated regions most commonly they prefer the three prime untranslated region and some of the cases though rare they can also bind to the five Prime untranslated region but that's much less frequent so how does Micro RNA regulate gene expression then microorganic and regular gene expression in two ways first of all it can down regulate the MRNA by degrading it just by associated with the rnai silencing complex it can chop off the MRNA and thereby less MRNA would be available to produce protein so less product would be formed there is also another way by which micro RNA can work that is interfering with the translation some of the cases the microorganic and the risk complex sits in a through three prime utr let's say but does not cleave the MRNA so it works like a road block for the ribosome or it interferes with the translation process that is also possible now let me tell you that micro rnas are present in a tissue specific and cell specific manner so let's say there are different cell types like epithelial cell one micro RNA might not be present in this cell but might be present in neuron and so might not be present in fibroblast again so there could be specific micro RNA which are very cell type specific but there could be also micro RNA which are present in pretty much all the cell types so depending on these function and availability micro RNA regulate the overall Gene regulatory networks in different cell types so how does that happen so imagine from a stem cell we have two alternate possibilities one epithelial cell one neuron now there are two Master regulatory Network here shown by Master regulator one and two so these Master Regulators are transcription factor and these transcription each of these transcription Factor regulates one particular gene expression module and each of these module actually suppress each other that's why in the stem cell State none of the Fate is acquired so one of the module has to dominate over the other module this is how the system is laid off and here comes the micro RNA imagine a micro RNA which is let's say micro RNA X this can suppress the master regulator Network 2. so as a result the master regulator transcription Factor would be produced less the gene module 2 would be poorly regulated or down regulated so now the repression of module 2 over module 1 would be would be gone and now module one would be the predominant gene expression module mediated by Master regulator one so it might lead to the fate towards an epithelial cell so this is how we saw how one possible way by which microorganic and regulate the selfie choice micro RNA not only is present in the cell but also present in secreted body fluids for example micro rnas can be found in cerebrospinal fluid one example is micro RNA 204 and it has been shown by scientists recently that microorganate 204 regulates the quiescence of stem cells in the brain region so it regulates the number of quiescent neuronal stem cells and that is super important for brain development micro rnas are also implicated in the context of cancer small RNA sequencing from the tumor some samples has identified there are several several micro rnas which gets upregulated in a cancer sample how does they regulate proliferation or cell division kinetics is something to note in the future years and but Micro rnas are super important in context of many diseases including cancer so let's ask that how one can study micro RNA experimentally so micro RNA can be detected with the help of small RNA sequencing but that's expensive so if you have you have to know about few microorganas let's say four or five micro rnas quantitative real-time PCR could be another alternative and very sensitive also fluorescence in situ hybridization can show you the intrinsic localization of a particular micro RNA inside the cell there are reporter assets as well in this reported assay there would be a reported Gene like gfp underneath the reporter the three prime utr of a Target MRNA would be provided anyway this reporter would be eventually transcribed and translated to give rise to gfp but imagine there is a micro RNA which binds to the three prime utr and degrades this particular this particular mRNA so in that context less amount of gfp would be produced so by looking at the gfp fluorescence one can get an idea about the regulation of micro RNA for this particular transcript and this is how one can possibly study micro RNA in the lab so I hope this video was useful if you like this video give it a quick thumbs up you can get more notes flash cards in my Facebook page also in Instagram please support our Channel using super thanks you can pay via PayPal paytm or UPI see you in next video