Comments on: Influenza viral RNA synthesis

By: Coverend

Coverend — Tue, 29 Nov 2011 21:43:00 +0000

So a negative sense genome is simply a template for transcription? Or are the nucleotide sequences assembled by addition to the 5′ carbon rather than the 3′?
Thanks!

By: reverse phone lookup

reverse phone lookup — Thu, 17 Nov 2011 21:23:00 +0000

Looks like you’ve done your research very well.

By: profvrr

profvrr — Tue, 13 Sep 2011 15:23:00 +0000

All influenza viral RNA synthesis is carried out by the viral RNA dependent RNA polymerase. The cap plus10-13 nucleotides are derived from host mRNAs.

By: profvrr

profvrr — Tue, 13 Sep 2011 15:22:00 +0000

For influenza virus, (+)vRNA and mRNA are different. (+)vRNA cannot be translated into protein. Both RNAs are produced by the viral RNA dependent RNA polymerase, two different forms of the enzyme.

By: Prijal

Prijal — Tue, 13 Sep 2011 09:49:00 +0000

The mRNA synthesis and (+)vRNA transcription confuses me. As I understood from this blog, these are two different steps (however, many articles say that mRNA can be used for translation and (-) vRNA formation). So, is the (+) mRNA strand formation catalyzed by viral RNA dependent RNA polymerase or by the host RNA polymerase?

By: Adam Abdulhafid

Adam Abdulhafid — Mon, 15 Aug 2011 02:40:00 +0000

If the virus doesn’t have a cap already then the viral RNA pol isn’t replicating the – to + then to -, so what is?

By: Viral rna | Moonshotvideo

Viral rna | Moonshotvideo — Mon, 30 May 2011 04:52:19 +0000

[...] Influenza viral RNA synthesisOnce the (-) strand influenza viral RNAs enter the nucleus, they serve as templates for the synthesis of mRNAs. These molecules are then transported back to the cytoplasm, where they direct the synthesis of viral proteins. … The influenza viral RNA polymerase is a primer-dependent enzyme. The enzyme cannot copy the (-) [...]

By: APBioStudent

APBioStudent — Sat, 02 Apr 2011 21:50:00 +0000

Thank you so much, this really helped for my powerpoint for AP Bio! I’m just not fully understanding cap snatching though…

By: profvrr

profvrr — Wed, 30 Mar 2011 18:28:00 +0000

Very good question – the answer depends on the virus. Viral RNA
synthesis includes all RNAs made by a virus; mRNAs and genome. So that
term includes viral replication (more accurately, viral genome
replication). For some viruses, such as poliovirus, the genome is the
same as mRNA; so viral RNA synthesis and viral genome replication are
the same. The more generic term ‘viral replication’ is often used to
mean production of new infectious particles.

By: Whatshisface01

Whatshisface01 — Wed, 30 Mar 2011 17:57:00 +0000

I’m slightly confused; what is the difference between viras synthesis and viral replication? Does synthesis involve forming new viral proteins, whereas replication involves forming new viral nucleic acids?

By: Leojh1985

Leojh1985 — Tue, 28 Sep 2010 06:40:35 +0000

I want to know whether there exists a chronological order of influenza protein synthesis？And any paper report？

By: profvrr

profvrr — Fri, 12 Feb 2010 03:54:07 +0000

The negative strand of RNA must have signals that direct its
incorporation into virions; the plus strand must lack these signals.
However, the specific sequences have not been identified. As for your
defense question - cells have internal defense mechanisms that sense
the presence of foreign RNA and attempt to destroy it. This is carried
out by the innate immune system - which we discussed here:
http://www.virology.ws/2009/06/03/innate-immune...

By: profvrr

profvrr — Thu, 11 Feb 2010 19:54:07 +0000

By: Student

Student — Sun, 07 Feb 2010 03:47:56 +0000

If the (-) strand RNA is also being converted into (+) strand RNA , what system is used for the virus to recognize which strand to take up in the virion? Also (and I know that this goes beyond the scope of this topic) but does the cell have any internal features that allow it to combat viral infections or is its only means of defense to signal the immune system and undergo apoptosis?

By: The error-prone ways of RNA synthesis

The error-prone ways of RNA synthesis — Mon, 11 May 2009 03:00:22 +0000

[...] that we have examined influenza viral RNA synthesis, it’s a good time to step back and look at a very important property of this step in viral [...]

By: profvrr

profvrr — Fri, 08 May 2009 23:39:25 +0000

Yes, the videos are far too fast, but no one would watch otherwise!
And yes, the replication time is directly related to how much of a
window you have for antivirals to be effective. For flu, that's within
48 hr, because it's a fast (acute) virus. For other, slower viruses,
you may have much more time.

By: Trine

Trine — Fri, 08 May 2009 23:31:14 +0000

Hey Vincent, thanks! I suppose that's another problem with the virus video, then. It makes it seem so quick, almost instantaneous. and it's not. it's hours long. Is the length of time – about 4 hours – related to how quickly you have take Tamiflu – within two days of symptoms – for it to really help?

By: profvrr

profvrr — Fri, 08 May 2009 23:11:16 +0000

Each step takes time. Virus binding, entry, RNA synthesis, protein
synthesis. Then (which we haven't covered yet) virion assembly and
budding. They all add up. Influenza is actually quite fast. Some
viruses require 24 hr to assemble and exit cells. There isn't any
particular step that is limiting, there are just a lot of them.
Remember the doubling time for a typical cell is 24 hr.

By: Trine

Trine — Fri, 08 May 2009 22:54:42 +0000

It takes longer than I thought. Do we know why it takes four hours? Is there a step that takes longer than the rest, that sort of holds it up?

By: profvrr

profvrr — Fri, 08 May 2009 20:04:48 +0000

The sialidases remove sialic acid from only a small part of the
respiratory tract, just enough to reduce viral entry. They are rapidly
regenerated and thus there is no negative effect on the host.
Certainly if sialic acids were removed permanently from all cells it
would be deterimental.

By: profvrr

profvrr — Fri, 08 May 2009 20:04:45 +0000

How quickly does RNA synthesis occur? Copying of each segment takes
only a few minutes. Once the RNAs are in the nucleus – which takes
minutes also – they are rapidly copied. New virus particles are
produced in the cell within ~4 hr.

By: Mauricio Carrillo-Tripp

Mauricio Carrillo-Tripp — Fri, 08 May 2009 15:46:58 +0000

Very informative, specially the link to the post on new antiviral drugs. In it, you mention: “DAS181, or Fludase, is unique in that it incorporates a sialidase that removes sialic acids from mucosal membranes, thereby preventing viral attachment via the HA glycoprotein.” and I thought, isn't this bad for the organism?, I mean, sialic acids are there for a reason, right?

By: trine

trine — Fri, 08 May 2009 13:49:37 +0000

How quickly does this happen? Is it almost instantaneously or a slow process?