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kappusha OP t1_j2ydgg9 wrote

Reply to comment by SignalDifficult5061 in How many times mRNA transcript can be translated before it's degraded or something like that? by kappusha

So next question is how many times per hour mRNA transcript gets translated on average?

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SignalDifficult5061 t1_j2ynm86 wrote

I would tend to think that has a worse chance at a useful and glib answer (although you may find some). For anything practical, that rate might not be super informative about what is going on.

It is harder to study because of differences in protein degradation rates and other things. High absolute numbers of a protein made per hour with a high decay rate can have the same ratio as a slow synthesis and slow degradation rate protein, There are a number of other technical challenges. Although there are certainly rates known for some individual mRNAs, and have been for some time, it is harder to look at that on the whole genome

That being said, the paper below suggests one to millions per generation (Figure S1 supplemental), which they define as a minimum of about 21.5 minutes (varies substantially).

The paper below is an E.coli example. It may very quite a bit in other organisms and cell types in multicellular organisms at least. life stage etc.

"Quantifying Absolute Protein Synthesis Rates Reveals Principles Underlying Allocation of Cellular Resources" https://www.sciencedirect.com/science/article/pii/S0092867414002323

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SignalDifficult5061 t1_j2yt44u wrote

Interestingly, there are some very weird things that could happen with that rate.

An extreme example I know of is Xenopus oocyte maturation. Oocyte maturation goes through a number of steps, in one of those the oocyte basically hoards a whole bunch of mRNA but doesn't do much with it (for like days), then at the next stage it makes a whole lot of protein but little mRNA.

So in this (somewhat extreme) example calculating the rate of proteins made per transcript is going to yield very different answers, and is also going to obscure what is really going on in the cell.

This is an extreme example, but I'm sure you can see the difficulties.

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kappusha OP t1_j30g0lj wrote

>That being said, the paper below suggests one to millions per generation (Figure S1 supplemental), which they define as a minimum of about 21.5 minutes (varies substantially).

Wait does it mean 10^6/(21,5*60)≈ 775 translations per second for one mRNA in e.coli on average ? Or am I confused?

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SignalDifficult5061 t1_j35uei8 wrote

That is how I read it, but I really like bourbon. like a lot. I like bourbon.

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kappusha OP t1_j35yicq wrote

it just sounds physically impossible

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SignalDifficult5061 t1_j3619jj wrote

Yeah, I thought so too. Then again, there are some enzymes that somehow outperform the theoretical maximum diffusion constant. Something about formate as a substrate.

I'm terrified if I talk about this some jerkwad will make some association with a vaccine or aquarium cleaner, and I don't like responsibility.

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[deleted] t1_j3fg2bs wrote

[removed]

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kappusha OP t1_j3fvtip wrote

Is there any way we can find out it? Like I don't know binding GFP to ribosomes and setting this up so complex will emit light if it translated one mRNA?

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Aus_scientist t1_j4upg4e wrote

Polysome profiling can give us an indication of translation kinetics. Basically, a transcript can have multiple ribosomes actively translating on it at once - so measuring this. Pairing this info with transcriptomic info you can get the rate of translation. And then knowing the transcript's degradation kinetics can give you an estimate.

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