This is a common feature of coronaviruses in general, and absolutely not unique to the CCP virus. Here's a paper from 2001 talking about is role in viral reproduction for coronaviruses:
https://link.springer.com/chapter/10.1007/978-1-4615-1325-4_68
"The 3′ poly (A) tail plays an important, but as yet undefined role in Coronavirus genome replication. To further examine the requirement for the Coronavirus poly(A) tail, we created truncated poly(A) mutant defective interfering (DI) RNAs and observed the effects on replication. Bovine Coronavirus (BCV) and mouse hepatitis Coronavirus A59 (MHV-A59) DI RNAs with tails of 5 or 10 A residues were replicated, albeit at delayed kinetics as compared to DI RNAs with wild type tail lengths (>50 A residues). A BCV DI RNA lacking a poly(A) tail was unable to replicate; however, a MHV DI lacking a tail did replicate following multiple virus passages. Poly(A) tail extension/repair was concurrent with robust replication of the tail mutants. Binding of the host factor poly(A)- binding protein (PABP) appeared to correlate with the ability of DI RNAs to be replicated. Poly(A) tail mutants that were compromised for replication, or that were unable to replicate at all exhibited less in vitro PABP interaction. The data support the importance of the poly(A) tail in Coronavirus replication and further delineate the minimal requirements for viral genome propagation."
---- so is it some kind of "end of code" signature?
they claim its a few a's sometimes and over 50 a's other times.
im not savvy enough on dna i guess.
I was unable to find anything that definitively deduces the mechanism behind this.
I will guess that this is related to the ways viral RNA replication is imperfect. It's possible that repeated As on the tail are reasonably successful at preventing partial replication of the RNA sequence. It's shorter and simpler than telomeres (which require multiple protein sequences to fully support), and other research has demonstrated that shorter viral RNA is more successful, so it's usual for it to be trimmed down far more than genetic material from cells.
This is a common feature of coronaviruses in general, and absolutely not unique to the CCP virus. Here's a paper from 2001 talking about is role in viral reproduction for coronaviruses: https://link.springer.com/chapter/10.1007/978-1-4615-1325-4_68
"The 3′ poly (A) tail plays an important, but as yet undefined role in Coronavirus genome replication. To further examine the requirement for the Coronavirus poly(A) tail, we created truncated poly(A) mutant defective interfering (DI) RNAs and observed the effects on replication. Bovine Coronavirus (BCV) and mouse hepatitis Coronavirus A59 (MHV-A59) DI RNAs with tails of 5 or 10 A residues were replicated, albeit at delayed kinetics as compared to DI RNAs with wild type tail lengths (>50 A residues). A BCV DI RNA lacking a poly(A) tail was unable to replicate; however, a MHV DI lacking a tail did replicate following multiple virus passages. Poly(A) tail extension/repair was concurrent with robust replication of the tail mutants. Binding of the host factor poly(A)- binding protein (PABP) appeared to correlate with the ability of DI RNAs to be replicated. Poly(A) tail mutants that were compromised for replication, or that were unable to replicate at all exhibited less in vitro PABP interaction. The data support the importance of the poly(A) tail in Coronavirus replication and further delineate the minimal requirements for viral genome propagation."
---- so is it some kind of "end of code" signature? they claim its a few a's sometimes and over 50 a's other times. im not savvy enough on dna i guess.
Good find because I had no idea such a thing would naturally occur, but the paper you've linked to indicates that it does.
I was unable to find anything that definitively deduces the mechanism behind this.
I will guess that this is related to the ways viral RNA replication is imperfect. It's possible that repeated As on the tail are reasonably successful at preventing partial replication of the RNA sequence. It's shorter and simpler than telomeres (which require multiple protein sequences to fully support), and other research has demonstrated that shorter viral RNA is more successful, so it's usual for it to be trimmed down far more than genetic material from cells.
Just a guess, though.