The poly(A) tail protects the 3' end of the final mRNA against ribonuclease digestion, it stabilizes the mRNA. In addition, it increases the efficient of translation of mRNA (i'm not sure how it increases efficiency, i'm gonna ask my teacher about it later).
The fact that it's complex doesn't mean it must have been created or driven by a greater force, it only means we don't have an explanation for it. I'm not saying it's impossible, that would be just as stupid to say that it's the only viable explanation. Our understanding of the universe is extremely limited, because of our limited ways of observing the micro and macroscopic. Therefore, we will never fully understand how everything works.
I mean imagine a single detail from the process is changed , Let’s say the addition of poly a tail is missing , it means that the mRNA wouldn’t be protected from nucleuses and the mRNA wouldn’t survive, then proteins wouldn’t be synthesised. Don’t you think that this whole complex process is organized randomly? Without a creator?
Actually it's more like a conveyor belt - the modern view is that capping happens at the start of transcription, and then while transcription is still going on, splicing occurs. Once transcription is complete, cleavage occurs and the polyA tail can be added. This differs from the traditional view put forward in this video, that splicing happens last.
Sometimes I feel like all of this molecular biology is a big fat fictional story made by someone and we all have to believe it :( At least all of this complicated stuff like how do u know the cleavage molecules bind and poly A come in and ughhh
A culmination of research is how we know this is what occurs. Try looking in Google Scholar for peer-reviewed publications that answer questions like yours. But it is probably from multiple papers and labs that brings it all together. 'Reviews' are the best way to learn about something that it took a lot of years and research to find out.
Yeah, we sit atop a vast mountain of ideas, ingenuity, and toil. So much knowledge. Ya know, many scientists spend their entire career, which can be decades long, working on some seemingly tiny tidbit of a molecular function, biological process, or cellular component that goes on within cells. Obtaining the evidence that u mentioned is what is really cool. People have been so clever coming up with experiments and technologocal devices that obtain the results or evidence. That goes for all scientific disciplines and others that are research based. The magic is actually great minds that have built this mountain and it will only get bigger and bigger.
I mean in a way, you are right. Science is something that always changes as new observations are made, but don't forget these kinds of things are all backed up by evidence, though it might seem like a bunch of nonsense at times (if you look into it, you'll find more info about these evidence and research). It fries your brain eh?
Hey. Isn't it CPSF-73 that acts as an hydrolase, and cleaves the mRNA downstream AAUAAA signal ? In the video, it's stated that it's the Poly(A)-polymerase.
That excision at the 3' end (that it will be the tip where the A's will be added) looks like an intron removal. It forms a loop that looks like a lariat.
The RNA processing is cotranscriptionally which includes splicing! Felt like the video suggested splicing starts after the RNA is being completely transcribed which is wrong as far as I know.
Good grief, not after! Splicing is happening in a co-transcriptional way, As splice sites get out of the polymerase complex, splicosome cuts them! PolyA signal is also the signal for splicing the last (!) exone. PolyA is added after all introns are spliced away. And there is also the alternative polyadenylation. I'm so tired of this mistake reoccurring in books/sites.
Not to mention there is a Cap Binding Protein attached to the Pol II CTD which...well it binds the cap, and hence it is not floating free like in the animation.
Thanks again for this information. BTW, is this model considered established yet? Or is it still tentative? (I found something from 2006, that indicates that it is the best supported theory, but that there is the similar allosteric model.)
I'm a little confused. Transcription continues until the a stop codon is encountered right? If cleavage simply slices off the end, does that mean the mRNA will be missing a stop codon? Wouldn't that just lead to a lot of Lysine being put at the end of proteins during translation?
they don't because people would then ask, "how do proteins work? How can they organize themselves? how can they make choices and decisions?" Universities can not have students questioning evolution.
This video unrightfully tells you that splicing occurs only after polyadenylation. Please note that splicing is known to happen DURING transcription already!
Which are the functions of the poly a tail?. I kind of know it has something to do with protection but I'm not really sure. I'll be glad if someone can help.
really eh? so random chemical reactions can assemble flagellums? Random magnetic forces can guide enzymes right inside RNAP2? Perhaps these things are happening, but you really think they are just random forces and reactions? Or are they all coordinated so perfectly together, that I would have greater odds getting married to Kate Upton than natural random process could organize into flawless and functional systems?
actually we do know how this stuff is triggered...take a 2nd year molecular bio class and you learn about all the small details. this video doesnt go into 3rd year and 4th year mechanisms, but its all understood. At the molecular level of things relating to transcription we know all the mechanisms. the only thing we arent very sure about is how and why when these mechanisms evolved over millions of years
it is the cleavage and polyadenylation specificity factor (CPSF) that cleaves pre-mRNA. Polyadenylation requires both cleavage of the pre-mRNA and polyadenylation at the cleavage site which req's CPSF, CstF, CF I, CF II, poly(A) polymerase, and RNA polymerase II. this video is for beginners and outdated tbh
+Chris L Because the RNA Polymerase 2 does not stop at the "correct" end for the mRNA. It just goes until it dissociates. The cleavage is necessary to get the correct mRNA end. Those sequences shown are the ones that allow the cleavage proteins to determine where this needs to occur.
can anyone help me out with this? Capping of eukaryotic mRNA involves modification of the first nucleotide of the polynucleotide strand:? A. phosphorylation of the 2' hydroxyl of the first nucleotide B. 5' to 5' transesterification of GTP C. addition of a dieoxy- nucleotide triosphospate to prevent further polymeration D. addition of a chain of adenine nucleotides
Well i've studied since then and i ended up with a somewhat different answer: protection from exonuclease cleavage, also transport from the nucleus to cytoplasm and assisting on the translation initiation by binding with the eIF4E
what scientist still don't know and will never is how all the processes are triggered how does this move there and know what it's function? it's Allah who does it all
Poly A polymerase didn't cut the mRNA ....there cpsf 73 which makes cut the mRNA ....and poly A polymerase only add Adenine residue to it.... please dont teach false
how is this a joke? explain how lumps of atoms can possibly have 1% of the intelligence required for these tasks. What's your explanation, other than to attack those who praise the creator of this incredible invention? For Gods sakes, a human like you could not do this, with a brain (I think so no?) and eyes, ears, nose, several years of high school at least (no?)... IF A HUMAN CAN'T DO THIS, WHY DO YOU THINK PROTEINS WHO ARE LUMPS OF ATOMS CAN????
Yes, anything that you can't wrap your head around is done by Allah. Just like in the ancient times when people couldn't wrap their head around what the Sun is they assumed it was god. lol.
Holy cow, I understood more in 2 mins than from my textbook.
Same 😂
Love the intro instrumental hardest biology intro ever!!
Excelent video!! After 10 y of posting, it still helps !!!!
The poly(A) tail protects the 3' end of the final mRNA against ribonuclease digestion, it stabilizes the mRNA. In addition, it increases the efficient of translation of mRNA (i'm not sure how it increases efficiency, i'm gonna ask my teacher about it later).
Did you ask your teacher?
I'd like to know 😁
The fact that it's complex doesn't mean it must have been created or driven by a greater force, it only means we don't have an explanation for it.
I'm not saying it's impossible, that would be just as stupid to say that it's the only viable explanation. Our understanding of the universe is extremely limited, because of our limited ways of observing the micro and macroscopic. Therefore, we will never fully understand how everything works.
didn’t ask
You just showed that there’s a God, a creator. You can’t just say that happened randomly by chemical reactions cause that sounds stupid
Allah creates all the world
I mean imagine a single detail from the process is changed , Let’s say the addition of poly a tail is missing , it means that the mRNA wouldn’t be protected from nucleuses and the mRNA wouldn’t survive, then proteins wouldn’t be synthesised. Don’t you think that this whole complex process is organized randomly? Without a creator?
Actually it's more like a conveyor belt - the modern view is that capping happens at the start of transcription, and then while transcription is still going on, splicing occurs. Once transcription is complete, cleavage occurs and the polyA tail can be added. This differs from the traditional view put forward in this video, that splicing happens last.
this is so fire, thanks so much for this animation!!
Sometimes I feel like all of this molecular biology is a big fat fictional story made by someone and we all have to believe it :( At least all of this complicated stuff like how do u know the cleavage molecules bind and poly A come in and ughhh
A culmination of research is how we know this is what occurs. Try looking in Google Scholar for peer-reviewed publications that answer questions like yours. But it is probably from multiple papers and labs that brings it all together. 'Reviews' are the best way to learn about something that it took a lot of years and research to find out.
Pretty much, except that it's supported by evidence.
Same thing goes for chemistry. It's just a way for us to understand nature.
Yeah, we sit atop a vast mountain of ideas, ingenuity, and toil. So much knowledge. Ya know, many scientists spend their entire career, which can be decades long, working on some seemingly tiny tidbit of a molecular function, biological process, or cellular component that goes on within cells. Obtaining the evidence that u mentioned is what is really cool. People have been so clever coming up with experiments and technologocal devices that obtain the results or evidence. That goes for all scientific disciplines and others that are research based. The magic is actually great minds that have built this mountain and it will only get bigger and bigger.
Nida Khan You are right because everything we study is somewhat hypothetical.
I mean in a way, you are right. Science is something that always changes as new observations are made, but don't forget these kinds of things are all backed up by evidence, though it might seem like a bunch of nonsense at times (if you look into it, you'll find more info about these evidence and research). It fries your brain eh?
Hey. Isn't it CPSF-73 that acts as an hydrolase, and cleaves the mRNA downstream AAUAAA signal ? In the video, it's stated that it's the Poly(A)-polymerase.
That excision at the 3' end (that it will be the tip where the A's will be added) looks like an intron removal. It forms a loop that looks like a lariat.
Merci beaucoup pour la video, cest tres bien, Daccord!!
The RNA processing is cotranscriptionally which includes splicing! Felt like the video suggested splicing starts after the RNA is being completely transcribed which is wrong as far as I know.
Good grief, not after! Splicing is happening in a co-transcriptional way, As splice sites get out of the polymerase complex, splicosome cuts them! PolyA signal is also the signal for splicing the last (!) exone. PolyA is added after all introns are spliced away. And there is also the alternative polyadenylation.
I'm so tired of this mistake reoccurring in books/sites.
Not to mention there is a Cap Binding Protein attached to the Pol II CTD which...well it binds the cap, and hence it is not floating free like in the animation.
Thanks again for this information. BTW, is this model considered established yet? Or is it still tentative? (I found something from 2006, that indicates that it is the best supported theory, but that there is the similar allosteric model.)
Thanks a lot! It is so usefull for my finals
Prachtig nummer Rob, je verrast mij!!!!
Makes more sense than my professor's explanation.
I'm a little confused. Transcription continues until the a stop codon is encountered right? If cleavage simply slices off the end, does that mean the mRNA will be missing a stop codon? Wouldn't that just lead to a lot of Lysine being put at the end of proteins during translation?
Not sure how accurate this is anymore. For more information on how transcription works look at the 2006 Nobel Prize in Chemistry to Roger Kornberg.
Does poly A polymerase or endonuclease cleave the mRNA?
Thanks for your film!
they don't because people would then ask,
"how do proteins work? How can they organize themselves? how can they make choices and decisions?"
Universities can not have students questioning evolution.
But doesn't splicing generally happen before tailing? Or tailing happens before the last splicing action?
Legendary video
Life is complex even at the molecular. Molecular machinery, many levels of regulation, heirarchical organization...
Great video!!! Would recommend 10/10😀
You are great.. Who made it..
Bcoz I couldn't understand this perfect before
I looked into this a little more and realized my mistake. I hadn't heard about the "Torpedo-model" though. I will have to look it up. Thanks!
where can i find the full track to the opening notes of the video?
This video unrightfully tells you that splicing occurs only after polyadenylation. Please note that splicing is known to happen DURING transcription already!
where does the Poly A polymerase go when it stops adding residues?
It's all just chemistry. Most the the processes actually *are* understood. This is just a beginner's video.
What us the significance of the poly A tail?
poly a polymerase is so cute
Beautiful. Thank you!
I really wish professors would show these videos.
Which are the functions of the poly a tail?. I kind of know it has something to do with protection but I'm not really sure. I'll be glad if someone can help.
Thank but if it was in more detail..it would have helped bettr
really eh? so random chemical reactions can assemble flagellums? Random magnetic forces can guide enzymes right inside RNAP2? Perhaps these things are happening, but you really think they are just random forces and reactions? Or are they all coordinated so perfectly together, that I would have greater odds getting married to Kate Upton than natural random process could organize into flawless and functional systems?
actually we do know how this stuff is triggered...take a 2nd year molecular bio class and you learn about all the small details. this video doesnt go into 3rd year and 4th year mechanisms, but its all understood. At the molecular level of things relating to transcription we know all the mechanisms. the only thing we arent very sure about is how and why when these mechanisms evolved over millions of years
Bravissimo ragazzi!
I really wish professors would teach our lectures xD
Too easy to understand thanks
The beginning looked like an old PS2 game
Why does poly a polymerase cleave the mrna?
it is the cleavage and polyadenylation specificity factor (CPSF) that cleaves pre-mRNA.
Polyadenylation requires both cleavage of the pre-mRNA and polyadenylation at the cleavage site which req's
CPSF, CstF, CF I, CF II, poly(A) polymerase, and RNA polymerase II.
this video is for beginners and outdated tbh
+Chris L Because the RNA Polymerase 2 does not stop at the "correct" end for the mRNA. It just goes until it dissociates. The cleavage is necessary to get the correct mRNA end. Those sequences shown are the ones that allow the cleavage proteins to determine where this needs to occur.
good teacher plz come to pakistan
this was helpful! thank you
Amazing. Thank you
why does it happen
can anyone help me out with this?
Capping of eukaryotic mRNA involves modification of the first nucleotide of the polynucleotide strand:?
A. phosphorylation of the 2' hydroxyl of the first nucleotide
B. 5' to 5' transesterification of GTP
C. addition of a dieoxy- nucleotide triosphospate to prevent further polymeration
D. addition of a chain of adenine nucleotides
It is B
that was amazing!
what is the purpose of the cap?
Well i've studied since then and i ended up with a somewhat different answer: protection from exonuclease cleavage, also transport from the nucleus to cytoplasm and assisting on the translation initiation by binding with the eIF4E
Can you permiss me to download this file? please...
It is very heplful for my end term of exam :(
+Út Lan NO!
Thank you so much!
thank you, thank you!
감사합니다!!
firstly, what the fuck.
secondly, thanks textbook for confusing me uselessly.
thirdly, what the fuck.
thank you!
Thanks a lot
Thank u
thanks
in gc uni of fsd
what scientist still don't know and will never is how all the processes are triggered how does this move there and know what it's function? it's Allah who does it all
very helpful thanks babe
Ahaha representing Pastafarianism I see, atta boy
makasih loh bg
thx
Poly A polymerase didn't cut the mRNA ....there cpsf 73 which makes cut the mRNA ....and poly A polymerase only add Adenine residue to it.... please dont teach false
Why are these educational videos always boring and filled with monotonous voices?
please we need tranlate
cap
lol
ratio
LOLOLOLOLOLOLOLOLLLOLLO bio
how is this a joke? explain how lumps of atoms can possibly have 1% of the intelligence required for these tasks. What's your explanation, other than to attack those who praise the creator of this incredible invention?
For Gods sakes, a human like you could not do this, with a brain (I think so no?) and eyes, ears, nose, several years of high school at least (no?)...
IF A HUMAN CAN'T DO THIS, WHY DO YOU THINK PROTEINS WHO ARE LUMPS OF ATOMS CAN????
Yes, anything that you can't wrap your head around is done by Allah. Just like in the ancient times when people couldn't wrap their head around what the Sun is they assumed it was god. lol.