Randy Schekman (HHMI & UCB) 3: How human cells secrete small RNAs in extracellular vesicles

[@MahirSayar]

How are these RNAs different from viruses?

[@mugogrog]

RNA is just a string of nucleobases if it has its own membrane outside a cell it's called an exosome, a virus is a complex organism that use RNA and multiply using it. It's notable that exosome RNA is usually a way smaller string of nucleobases than that in a virus since the viral RNA codes for the structure of the complete virus. At least that is how I as a layman have understood it.

[@Littleprinceleon]

First and foremost: the proteinaceous structure of viruses (whether RNA or DNA based genome) has evolved to protect the genomic material outside the host body to enable it's spreading from one organism to another. Exosomes remain active in the body... Some of the the viral proteins enable to choose specific target cells (while with exosomes it seems to be more general) and in many viruses (such as in SARS-CoV2) a surface protein actively fuses the viral particle (virion) with the target cell. miRNA are called microRNA exactly because they are hundred time smaller than viral RNA which are denoted genomic, since they code for more genes which directly enable the replication of this genome (and ultimately the whole virus). The picture is sometimes more complex (just as it is in almost any biological process): some viruses (most notoriously the retroviruses) have inactive counterparts called vírus like particles (VLP)...which cannot spread the way viruses do. Also there are (retro-)trans-posones and other mobile genetic elements which complicate the picture for layperson....

[@tpf4292]

Randy's experiments are always so satisfying...

[@AlphaOmega888]

13:02 He's literally explaining how they made COVID-19

[@trabiccolo879]

The only idea I have is that for RT - PCR test, RNA Exosome or RNA Virus may both trigger a Positive, in the same way.

[@MyLordexe]

yup.

[@amandapoyner8141]

Yes, Exosomes are apparently easily programmed to target information to any other type of cells in the human body... Like the lungs. Aggressive and fast acting cancers.

[@carloc8763]

@@trabiccolo879 totally agree, that is why I am now concerned when I hear WHO officials arguing that they could take away people from they homes to stop this "virus" www.lifesitenews.com/news/tucker-carlson-rips-who-emergency-expert-for-call-to-raid-homes-remove-sick-family-members

[@Mike-vx5hw]

From what I understand a “virus” is indistinguishable from an exosome...so ya, a lot of extra positive tests would quickly add up.

[@SrinivashM29]

Wonderful lecture, really enjoyed it. Thank you Prof. Schekman.

[@BioMedUSA]

Very lucid explanation and thought flow of the experimental progressions. My question is why were the assays done at 30 degrees C rather than 37C? At physiological temperatures, this would dramatically affect and increase membrane fluidity (at 37C vs 30C) of the exosomes and likely associated enzymatic activity.

[@mememachine2586]

I have the same question

[@JuYoung-y8g]

Great lecture! thank you professor. from South Korea

[@jozsefolasz8702]

Wonderful lectures, thank you.

[@rafaelescate3618]

Great Dr. Schekman, thank you

[@simonroome5858]

Didn't understand much of that. Thumbs up anyway, lots of technical information, well presented.

[@teaezra5916]

Could our idea of viruses be completely wrong? Could viruses actually be exosomes? Has this been studied?

[@amandapoyner8141]

Yes. Think nano.

[@Mike-vx5hw]

My thoughts exactly... I’ve found limited study on the subject that does suggests it is possible.

[@belliotrungy9107]

No. Viruses have been studied in many species, including bacteria and match up to historical records. While exosomes are new and exciting and some overlap in mechanisms is interesting making that leap doesn't add up.

[@belliotrungy9107]

@@SueSue-mp2iu I read this already from your other post. I'm not sure if you're a Russian pushing disinformation or just have no real background in biology. It's really not that exciting a paper. Interesting! But not what you think it is......

[@belliotrungy9107]

@@SueSue-mp2iu again I already read that one too and while exosomes as relevant intercellular communication bubbles are new and interesting they do not at all debunk the well established field of virology.

[@bethaniamacedo9622]

OBRIGADA. SOU DO BRASIL E ASSISTO SUAS AULAS COM TRADUÇÃO.

[@trabiccolo879]

Can we distinguish an exosome from a virus, as an objective of RNA detection (RT - PCR) or under the Electron Microscope?

[@AlphaOmega888]

13:28 he seems to be explaining exactly how to engineer COVID-19

[@trabiccolo879]

@@AlphaOmega888 how do you mean?

[@skinnygumbo2700]

Of course you can distinguish an exosome from a virus! An exosome contains your own genetic material, the virus contains foreign DNA/RNA. The primers designed for RT-PCR are specific to a RNA sequence you only find in a virus.

[@hermangoranov3196]

​@@skinnygumbo2700 No. its not work like that. they only see simillarity of sars-cov-2 with previous sars. 80% simmilarity my ass, trash paper, even apes with human is better (Well, thats mean the primers is not credible). You better give me source/paper that already show human to human transmision on china, and how they found it or detect it. Sadly, WHO delete the paper on official site, you can found most dead link on. www.who.int/csr/don/12-january-2020-novel-coronavirus-china/en/ wjw.wuhan.gov.cn/front/web/showDetail/2020011109036

[@Littleprinceleon]

@@skinnygumbo2700 I appreciate the good work of your attempt at trying to spread basic knowledge in molecular biology. However, I do not think anymore that it is really worth of it. As you can see from Herman's response above: sadly even the more rational ones are deceived by sophisticated conspiracies. Only if they would take the solemnity and patience to actually understand at least the fu.ing principles of PCR: First, that one of the primer pairs can be similar or even identical to whatever sequence in whatever genome, if the other pair will not bind to that target (or bind it in some large distance from the first one), then there will be no amplification. Second, these conspirators should finally realise that the researchers used degenerate (not hundred percent homologous) primers (based on the 2003 SARS virus genome) ONLY for the very first identification steps of this new virus (later named SARS-CoV2)...but all the following PCR test use more specific primers. They should also know, that even if 90% of the primer has homology to a sequence, but it's 3' end lacks homology, than it will not be able to serve as primer for the polymerase, so again no amplification (meaning no PCR). These are the three not so trivial but basic points about primers in PCR techniques: if a paranoid layperson doesn't understand these than can be easily led astray. But this kind of attitude wouldn't fit their world views requiring global conspiracies and pseudo-science in order to fill in the enormous gaps in actual knowledge (which are not to be ashamed of since molecular biology or worldwide economics or global sociology... are topics which can be mastered only in many years as a professional or greatly understood only in one-two decades as a hobby...). So what remains for those areas of life which we know little of: Rational believes.... But again if one starts with conspiracies (however rationalized ones) (s)he will end up with disbelief in communities other then those supporting his/her stance. And those who is not capable to acknowledge that he/she has flows in some of the basic knowledge about the topic will argue round and round reinforcing only the basic bias and contributing to even more complex confusion in those with similar mentality

[@vidyaborah8320]

Thank you. Dr. S chek an.

[@toutours3244]

Nice lecture, would be better with some reading materials

[@bethaniamacedo9622]

SOU PROFESSORA DA REDE ESTADUAL. NA CIDADE DE LAGOA NOVA, ESTADO DO RIO GRANDE DO NORTE. BRASIL

[@numericalcode]

No wonder he’s a Nobel laureate

[@dantethedemon9277]

A VIRUS IS AN EXOSOME

[@skinnygumbo2700]

Bwahahahaha.

[@dantethedemon9277]

@@skinnygumbo2700 what

[@kdcruz75]

This is how they know that spike protein can be weaponised...

[@azu0016]

@@kdcruz75 As far as I know, designing an entirely new gene and being able to to predict how its protein product folds & functions for something as large as a spike protein is still way, way beyond human capacity. In microbial genetics (my area of study) we still have to purify whatever effector protein we target and study their effect via experiment, even when we know the exact gene and its exact sequence - no, you can't just look at a sequence and know what it's protein does. Similarly, you cannot say "oh I'd modify this gene by x base pairs and that will make this protein do y". Unless you're inserting an entire gene, promoter etc. with known function... which isn't the case of covid spike protein. I guess you can still brute force through random mutations + selection if you do want to "weaponize" something - which can be done in any high-school level lab since like 1960s and everyone knows it...

[@emanuele2398]

Thank you.

[@lastchance8142]

My daughter wants to be a lab rat in biological research, yet I'm the one watching all these ibiology videos. Go figure!

[@homefrontforge]

My daughter studied food science and while she took the organic bio classes I watched all these videos. So...same

[@فيديوهاتعلىاليوتيوب]

How can science bring the youth back to the old man? How can young people be brought back to the elderly? . We need to invent drugs and treatments to remove signs of aging .We need drugs and treatments to stop the aging Also . Please deliver my letter to doctors And owners of medical laboratories for treatment

[@skinnygumbo2700]

Why? If we don't die, nobody can be born. Are we that selfish?

[@فيديوهاتعلىاليوتيوب]

Human cells

[@harimari3967]

Chinese hamster ovary cell culture having some black dot like particles in spent media..i dont know it is contamination or not..i guess it is micro vesicles or Exosomes??

[@azu0016]

In most cases I would first assume mycoplasma or bacterial contamination, especially if you're subculturing a lot. Imo most likely bacteria, since they are the most noticable and ususally appear as black dots.