Carapucha 5': Diferenzas entre revisións
Contido eliminado Contido engadido
Liña 31:
==Función da carapucha 5′==
A carapucha 5′ ten 4 funcións principais:
#Regulación da exportación nuclear dos ARNm.<ref>{{cite journal|last1=Visa|first1=N.|last2=Izaurralde|first2=E.|last3=Ferreira|first3=J.|last4=Daneholt|first4=B.|last5=Mattaj|first5=I. W.|title=A nuclear cap-binding complex binds Balbiani ring pre-mRNA cotranscriptionally and accompanies the ribonucleoprotein particle during nuclear export|journal=The Journal of Cell Biology|date=1 April 1996|volume=133|issue=1|pages=5–14|doi=10.1083/jcb.133.1.5|url=http://jcb.rupress.org/content/133/1/5.abstract|accessdate=23 November 2014}}</ref><ref>{{cite journal|last1=Lewis|first1=Joe D.|last2=Izaurralde|first2=Elisa|title=The Role of the Cap Structure in RNA Processing and Nuclear Export|journal=European Journal of Biochemistry|date=15 July 1997|volume=247|issue=2|pages=461–469|doi=10.1111/j.1432-1033.1997.00461.x|url=http://onlinelibrary.wiley.com/doi/10.1111/j.1432-1033.1997.00461.x/abstract|accessdate=23 November 2014}}</ref>
#Prevención da degradación por [[exonuclease]]s do ARNm.]];<ref>{{cite journal|last1=Evdokimova|first1=Valentina|last2=Ruzanov|first2=Peter|last3=Imataka|first3=Hiroaki|last4=Raught|first4=Brian|last5=Svitkin|first5=Yuri|last6=Ovchinnikov|first6=Lev P.|last7=Sonenberg|first7=Nahum|title=The major mRNA-associated protein YB-1 is a potent 5' cap-dependent mRNA stabilizer|journal=The EMBO Journal|date=1 October 2001|volume=20|issue=19|pages=5491–5502|doi=10.1093/emboj/20.19.5491|url=http://onlinelibrary.wiley.com/doi/10.1093/emboj/20.19.5491/full|accessdate=23 November 2014}}</ref><ref>{{cite journal|last1=Gao|first1=Min|last2=Fritz|first2=David T.|last3=Ford|first3=Lance P.|last4=Wilusz|first4=Jeffrey|title=Interaction between a Poly(A)-Specific Ribonuclease and the 5′ Cap Influences mRNA Deadenylation Rates In Vitro|journal=Molecular Cell|date=March 2000|volume=5|issue=3|pages=479–488|doi=10.1016/S1097-2765(00)80442-6|url=http://www.sciencedirect.com/science/article/pii/S1097276500804426|accessdate=23 November 2014}}</ref><ref>{{cite journal|last1=Burkard|first1=K. T. D.|last2=Butler|first2=J. S.|title=A Nuclear 3'-5' Exonuclease Involved in mRNA Degradation Interacts with Poly(A) Polymerase and the hnRNA Protein Npl3p|journal=Molecular and Cellular Biology|date=15 January 2000|volume=20|issue=2|pages=604–616|doi=10.1128/MCB.20.2.604-616.2000|url=http://mcb.asm.org/content/20/2/604.short|accessdate=23 November 2014}}</ref>
#Promoción da tradución doa ARNm.)<ref name=shatkin /><ref name=banerjee /><ref name=sonenberg />
#Promoción da excisión do [[intrón]] máis próximo ao extremo 5′.<ref name=konarska1984>{{cite journal|last1=Konarska|first1=Maria M.|last2=Padgett|first2=Richard A.|last3=Sharp|first3=Phillip A.|title=Recognition of cap structure in splicing in vitro of mRNA precursors|journal=Cell|date=October 1984|volume=38|issue=3|pages=731–736|doi=10.1016/0092-8674(84)90268-X|url=http://www.sciencedirect.com/science/article/pii/009286748490268X|accessdate=12 December 2014}}</ref><ref>{{cita web |url=http://www.ncbi.nlm.nih.gov/pubmed/6567484 |title=Recognition of cap structure in splicing in vitro of mRNA precursors |deadurl=no |acceso=11 December 2012}}</ref>
A exportación nuclear do ARN está regulada polo [[complexo de unión á carapucha]] (''cap binbing complex'', CBC), que se une exclusivamente aos ARN con carapucha. O CBC é recoñecido despois polo complexo dos [[poro nuclear|poros nucleares]] e exportado. Unha vez no [[citoplasma]] despois da primeira rolda de tradución do ARNm, o CBC é substituído polos [[factor de transcrición|factores de transcrición]] [[eIF-4E]] e [[eIF-4G]]. Este complexo é despois recoñecido pola outra maquinaria de iniciación da tradución incluído o [[ribosoma]].<ref name=Kapp2004>{{cita publicación | last1 = Kapp | first1 = L.D. | last2 = Lorsch | first2 = J.R. | year = 2004 | title = The Molecular Mechanics of Eukaryotic Translation | journal = Annual Review of Biochemistry | volume = 73 | issue = 1 | pages = 657–704 | doi = 10.1146/annurev.biochem.73.030403.080419 | url = http://www.ebc.ee/loengud/valgu_biosyntees_2007/Supplement_Eukaryotic_translation.pdf | pmid = 15189156}}</ref>
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