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|WikiProject Molecular and Cellular Biology||(Rated GA-class, High-importance)|
Move to mRNA
I think this should be moved to mRNA under the mRNA structure heading.--Plociam 20:26, 1 August 2005 (UTC)
The subject is already well covered in MRNA#Eukaryotic_pre-mRNA_processing, and the link away from that page is irrelevant. Reccomend mergeing & deletion of stub. Vermiculus 12:13, 30 March 2006 (UTC)
This article is getting to big for integration into mRNA processing. Also, breaking it into a simple introduction in mRNA processing and this more detailed page helps readers. Like this they are not swamped with details but can chose to read more. Jasu 19:23, 23 May 2007 (UTC)
Description of the polyadenylation reaction : things to be corrected.
The present description and the drawing of the reaction are wrong :
the poly(A) polymerase (PAP), the CSPF, and the poly(A) tail regulator PABPN1 (the first PABPN1 bound to the 11 AMP residues added), must be interacting as a tripartite complex during the entire reaction of polyadenylation, since the processivity (that is the ability to add an AMP per catalytic cycle without dissociating from the 3'OH of the RNA between each catalytic cycle) of mammalian PAP relies on this tripartite complex.
The current model of termination for the mammalian polyadenylation reaction suggests that the PAPBN1/poly(A)250-300 tail forms a globular shaped RNP (ribonucleoparticule) of about 20 nm in diameter, and that this could sterically disrupt the tripartite complex mentionned above, leading to a change from processive to distributive activity of PAP, and therefore termination.
The drawing should in fact show the CPSF/PAP/firstPABPN1 complex at the site of cleavage, and as the poly(A) tail grows, the number of AMP residues increase, but the 3'OH end of the RNA always stays in contact with PAP located near CPSF, leading to the formation of a buckle of poly(A), PABPN1 proteins bound to it.
The current drawing shows PAP at the end of the RNA, with no interaction with CPSF or PABPN1 : in this case, PAP couldn't be able to add the poly(A) tail with real efficiency.
For references, type Elmar Wahle in pubmed, or see :
Also, the poly-A tail is formed by a lot of ADENINE molecules, not ADENOSINE.
188.8.131.52 16:50, 8 February 2007 (UTC)Austin
No, the poly(A) tail is indeed formed by adenosines, i.e nucleotides (ribose+base). Adenine is just the name of the base.
miRNA's do not promote degradation of mRNA transcripts, siRNA's do this. miRNA's are involved in inhibition of translation only. — Preceding unsigned comment added by 184.108.40.206 (talk) 20:37, 17 April 2014 (UTC)
FUNCTION OF POLY-A
This article has nothing on the function of the poly A tail.
A minireview on the different functions of poly A tailing in eukaryotes and bacteria: The Poly(A) Tail of mRNAs: Bodyguard in Eukaryotes, Scavenger in Bacteria. Cell , Volume 111 , Issue 5 , Pages 611 - 613 M . Dreyfus , P . Régnier —Preceding unsigned comment added by 220.127.116.11 (talk) 08:10, 11 June 2008 (UTC)
The article talks about how the poly-A tail is constructed, but makes only token references to how it is catabolized. Given that WP has no article on deadenylation, I think this would be a good place to talk about it. Especially considering that polyadenylation and the rate of deadenylation appears to be an important mRNA regulatory mechanism. - Psyno 08:13, 5 July 2007 (UTC)
Prokaryotes vs. Eukaryotes
I guess people are quick to learn that Poly-A occurs in Eukaryotes. Then they will see this sentence: "Some prokaryotic mRNAs also are polyadenylated, although the polyadenine tail's function is different from that in eukaryotes." but there is no link/evidence for this. Note, I dont doubt this at all, in fact I have a few textbooks that mention this, but I think wikipedia should mention from where exactly this information has been gathered. —Preceding unsigned comment added by 18.104.22.168 (talk) 12:51, 16 June 2008 (UTC)
Genetically Modified plants
What could be helpful is a explanation (or separate) article about the problems of expressing prokaryote genomes (such as Bt toxins) in eukaryotes (such as plant cells), especially in the development of GM crops. One issue is that eukaryote cell machinery wrongly polyadenylates prokaryote mRNA, because it recognizes certain stretches of the RNA as signals for adenylation. — Preceding unsigned comment added by 22.214.171.124 (talk) 21:39, 30 May 2011 (UTC)