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Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
71–80 of 125 posts
Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#72Earlier quoted context omitted.
This is true, but perhaps worth noting the nuclear transport function of polyA tails don't come into play for coronavirus. The payload of coronavirus is a positive-sense single-stranded RNA. Which means it does not need to enter the nucleus for preprocessing and can basically just start replicating shortly after entering a cell. See diagram... https://upload.wikimedia.org/wikipedia/commons/f/f4/Coronavi... There migh…
I don't think the genome has a specific length of the tail (33 is a consensus length) During genomic assays, the poly a tail will not be a specific length, but a single consensus sequence is still provided. This was also posted in the first comment: > Similar to eukaryotic mRNA, the positive-strand coronavirus genome of ~30 kilobases is 5’-capped and 3’-polyadenylated. It has been demonstrated that the length of the…
The polyA tail isn't even coded by the genome, it's added after transcription by a processive polyadenylation multiprotein complex with the final tally being the result of partially stochastic processes. So yeah, agreed, the number of adenines is variable.
Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#73[flagged]
Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#74[flagged]
Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#75Earlier quoted context omitted.
Is regex a drug feature we are building towards?
You can't parse DNA with regex.
They used to say that about email addresses. But hold my beer and I'll be back in like a month with some buggy half-assed crap that kinda does the job and only occasionally crashes the system!
Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#76Earlier quoted context omitted.
Can you add any number of A's, or just 1, or shorten it by 1, and it still is functional?
The number of adenine repeats that confer functional properties is quite variable but it definitely needs to be more than "just 1". I've seen anywhere from 25-250 used in designed plasmids. The exact number people use in their engineered sequence is based on a number of factors, not all of them scientific in nature (e.g. companies charge per basepair synthesize a bespoke polypeptide; e.g. you copied the sequence from…
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Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#77Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#78The top answer at the link explains it best: Good observation! The 3' poly(A) tail is actually a very common feature of positive-strand RNA viruses, including coronaviruses and picornaviruses. For coronaviruses in particular, we know that the poly(A) tail is required for replication, functioning in conjunction with the 3' untranslated region (UTR) as a cis-acting signal for negative strand synthesis and attachment to…
Can a drug target that sequence specifically?
Poly-A binding proteins naturally exist. They are used to regulate translation and to sequester mRNA during heat shock stress, IIRC. This prevents mistranslation, again IIRC.
https://faseb.onlinelibrary.wiley.com/doi/10.1096/fasebj.31....
Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#79This ending is the result of the Lisp closing parenthesis being important enough to be directly mapped to a dedicated nucleotide base.
Re: Why does the SARS-Cov2 genome end in aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa? (2020)
#80[flagged]