Splicing and 3' end formation in the definition of nonsense-mediated decay-competent human beta-globin mRNPs.
Premature translation termination codons are common causes of genetic disorders. mRNAs with such mutations are degraded by a surveillance mechanism termed nonsense-mediated decay (NMD), which represents a phylogenetically widely conserved post-transcriptional mechanism for the quality control of gene expression. How NMD-competent mRNPs are formed and specified remains a central question. Here, we have used human beta-globin mRNA as a model system to address the role of splicing and polyadenylation for human NMD. We show that (i) splicing is an indispensable component of the human beta-globin NMD pathway, which cannot be compensated for by exonic beta-globin 'failsafe' sequences; (ii) the spatial requirements of human beta-globin NMD, as signified by the maximal distance of the nonsense mutation to the final exon-exon junction, are less constrained than in yeast; and (iii) non-polyadenylated mRNAs with a histone 3' end are NMD competent. Thus, the formation of NMD-competent mRNP particles critically depends on splicing but does not require the presence of a poly(A) tail.
Neu-Yilik
G
G
Children's Hospital, Charité, Humboldt University, Augustenburger Platz 1, D-13353 Berlin, Germany.
Gehring
N H
NH
Thermann
R
R
Frede
U
U
Hentze
M W
MW
Kulozik
A E
AE
D001483:Base Sequence; D018389:Codon, Nonsense / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D005914:Globins / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D009154:Mutation; D011061:Poly A / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012261:Ribonucleoproteins / Q000235:genetics* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D018389:Codon, Nonsense; D017931:DNA Primers; D012333:RNA, Messenger; D012261:Ribonucleoproteins; C026452:messenger ribonucleoprotein; D011061:Poly A; D005914:Globins