Nematode m7GpppG and m3(2,2,7)GpppG decapping: activities in Ascaris embryos and characterization of C. elegans scavenger DcpS.
RNA
; 10(10): 1609-24, 2004 Oct.
Article
en En
| MEDLINE
| ID: mdl-15383679
A spliced leader contributes the mature 5'ends of many mRNAs in trans-splicing organisms. Trans-spliced metazoan mRNAs acquire an m3(2,2,7)GpppN cap from the added spliced leader exon. The presence of these caps, along with the typical m7GpppN cap on non-trans-spliced mRNAs, requires that cellular mRNA cap-binding proteins and mRNA metabolism deal with different cap structures. We have developed and used an in vitro system to examine mRNA degradation and decapping activities in nematode embryo extracts. The predominant pathway of mRNA decay is a 3' to 5' pathway with exoribonuclease degradation of the RNA followed by hydrolysis of resulting mRNA cap by a scavenger (DcpS-like) decapping activity. Direct decapping of mRNA by a Dcp1/Dcp2-like activity does occur, but is approximately 15-fold less active than the 3' to 5' pathway. The DcpS-like activity in nematode embryo extracts hydrolyzes both m7GpppG and m3(2,2,7)GpppG dinucleoside triphosphates. The Dcp1/Dcp2-like activity in extracts also hydrolyzes these two cap structures at the 5' ends of RNAs. Interestingly, recombinant nematode DcpS differs from its human ortholog in its substrate length requirement and in its capacity to hydrolyze m3(2,2,7)GpppG.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ascaris
/
Caperuzas de ARN
/
Fosfatos de Dinucleósidos
/
Caenorhabditis elegans
/
ARN de Helminto
Límite:
Animals
Idioma:
En
Revista:
RNA
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2004
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Estados Unidos