Talk:Messenger RNA

mRNA structure
Don't have time now, but mRNA in eukaryotes should be circular because if eIF4 class cap recognition proteins and PABPI.

Polyadenylation step could be more detailed
It could be detailed, but the already existing article (see http://en.wikipedia.org/wiki/Polyadenylation) must be partially corrected by the following indications :

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 :

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=7852352&query_hl=3&itool=pubmed_DocSum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=8440247&query_hl=3&itool=pubmed_DocSum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=1878970&query_hl=3&itool=pubmed_DocSum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=12853485&query_hl=3&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=11994003&query_hl=3&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=10731412&query_hl=3&itool=pubmed_docsum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=9061026&query_hl=3&itool=pubmed_DocSum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=9175430&query_hl=3&itool=pubmed_DocSum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=8428968&query_hl=3&itool=pubmed_DocSum

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_uids=1993684&query_hl=3&itool=pubmed_DocSum