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Decapping is preceded by 3' uridylation in a novel pathway of bulk mRNA turnover.

Rissland OS, Norbury CJ - Nat. Struct. Mol. Biol. (2009)

Bottom Line: Second, Cid1-dependent uridylation of polyadenylated mRNAs, such as act1, hcn1 and urg1, seems to stimulate decapping as part of a novel mRNA turnover pathway.Accordingly, urg1 mRNA is stabilized in cid1Delta cells.Uridylation and deadenylation act redundantly to stimulate decapping, and our data suggest that uridylation-dependent decapping is mediated by the Lsm1-7 complex.

View Article: PubMed Central - PubMed

Affiliation: Sir William Dunn School of Pathology, University of Oxford, UK.

ABSTRACT
Both end structures of eukaryotic mRNAs, namely the 5' cap and 3' poly(A) tail, are necessary for transcript stability, and loss of either is sufficient to stimulate decay. mRNA turnover is classically thought to be initiated by deadenylation, as has been particularly well described in Saccharomyces cerevisiae. Here we describe two additional, parallel decay pathways in the fission yeast Schizosaccharomyces pombe. First, in fission yeast mRNA decapping is frequently independent of deadenylation. Second, Cid1-dependent uridylation of polyadenylated mRNAs, such as act1, hcn1 and urg1, seems to stimulate decapping as part of a novel mRNA turnover pathway. Accordingly, urg1 mRNA is stabilized in cid1Delta cells. Uridylation and deadenylation act redundantly to stimulate decapping, and our data suggest that uridylation-dependent decapping is mediated by the Lsm1-7 complex. As human cells contain Cid1 orthologs, uridylation may form the basis of a widespread, conserved mechanism of mRNA decay.

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Decapping of mRNA can be independent of deadenylation(a) Overview of the cRACE procedures used to capture ends of decapped transcripts (gray) and mature transcripts (white). For details see Methods. (b, c) The 5′ (b) and 3′ (c) ends of various types of act1 cRACE sequences are plotted as the distance (in nt, as indicated on the horizontal axis) from the start codon. The open reading frame (ORF) is marked with a line. (d) Poly(A) tail lengths of decapped [black; 40 sequences] and capped [white; 20 sequences] act1 cRACE sequences were binned into groups of ten nt. Tail lengths were then plotted as the percentage of adenylated species. (e) Box-and-whisker plots of poly(A) tail lengths found on six different decapped transcripts, act1, adh1, gar2, hcn1, pof9 and urg1 (n=40, 16, 11, 12, 8 and 39 respectively). This plot depicts the quartiles of poly(A) tail length with the whiskers representing the range of each data set, the boxplot demarcating the second and third quartiles, which are separated by the median.
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Figure 1: Decapping of mRNA can be independent of deadenylation(a) Overview of the cRACE procedures used to capture ends of decapped transcripts (gray) and mature transcripts (white). For details see Methods. (b, c) The 5′ (b) and 3′ (c) ends of various types of act1 cRACE sequences are plotted as the distance (in nt, as indicated on the horizontal axis) from the start codon. The open reading frame (ORF) is marked with a line. (d) Poly(A) tail lengths of decapped [black; 40 sequences] and capped [white; 20 sequences] act1 cRACE sequences were binned into groups of ten nt. Tail lengths were then plotted as the percentage of adenylated species. (e) Box-and-whisker plots of poly(A) tail lengths found on six different decapped transcripts, act1, adh1, gar2, hcn1, pof9 and urg1 (n=40, 16, 11, 12, 8 and 39 respectively). This plot depicts the quartiles of poly(A) tail length with the whiskers representing the range of each data set, the boxplot demarcating the second and third quartiles, which are separated by the median.

Mentions: To dissect RNA decay pathways in fission yeast, we employed the cRACE technique6. A tail-independent method of capturing 3′ and 5′ ends, this procedure allows distinction between decapped and capped mRNAs (Fig. 1a). Decapped and capped act1 transcripts from exponentially growing wild-type (WT) cells were first examined.


Decapping is preceded by 3' uridylation in a novel pathway of bulk mRNA turnover.

Rissland OS, Norbury CJ - Nat. Struct. Mol. Biol. (2009)

Decapping of mRNA can be independent of deadenylation(a) Overview of the cRACE procedures used to capture ends of decapped transcripts (gray) and mature transcripts (white). For details see Methods. (b, c) The 5′ (b) and 3′ (c) ends of various types of act1 cRACE sequences are plotted as the distance (in nt, as indicated on the horizontal axis) from the start codon. The open reading frame (ORF) is marked with a line. (d) Poly(A) tail lengths of decapped [black; 40 sequences] and capped [white; 20 sequences] act1 cRACE sequences were binned into groups of ten nt. Tail lengths were then plotted as the percentage of adenylated species. (e) Box-and-whisker plots of poly(A) tail lengths found on six different decapped transcripts, act1, adh1, gar2, hcn1, pof9 and urg1 (n=40, 16, 11, 12, 8 and 39 respectively). This plot depicts the quartiles of poly(A) tail length with the whiskers representing the range of each data set, the boxplot demarcating the second and third quartiles, which are separated by the median.
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Related In: Results  -  Collection

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Figure 1: Decapping of mRNA can be independent of deadenylation(a) Overview of the cRACE procedures used to capture ends of decapped transcripts (gray) and mature transcripts (white). For details see Methods. (b, c) The 5′ (b) and 3′ (c) ends of various types of act1 cRACE sequences are plotted as the distance (in nt, as indicated on the horizontal axis) from the start codon. The open reading frame (ORF) is marked with a line. (d) Poly(A) tail lengths of decapped [black; 40 sequences] and capped [white; 20 sequences] act1 cRACE sequences were binned into groups of ten nt. Tail lengths were then plotted as the percentage of adenylated species. (e) Box-and-whisker plots of poly(A) tail lengths found on six different decapped transcripts, act1, adh1, gar2, hcn1, pof9 and urg1 (n=40, 16, 11, 12, 8 and 39 respectively). This plot depicts the quartiles of poly(A) tail length with the whiskers representing the range of each data set, the boxplot demarcating the second and third quartiles, which are separated by the median.
Mentions: To dissect RNA decay pathways in fission yeast, we employed the cRACE technique6. A tail-independent method of capturing 3′ and 5′ ends, this procedure allows distinction between decapped and capped mRNAs (Fig. 1a). Decapped and capped act1 transcripts from exponentially growing wild-type (WT) cells were first examined.

Bottom Line: Second, Cid1-dependent uridylation of polyadenylated mRNAs, such as act1, hcn1 and urg1, seems to stimulate decapping as part of a novel mRNA turnover pathway.Accordingly, urg1 mRNA is stabilized in cid1Delta cells.Uridylation and deadenylation act redundantly to stimulate decapping, and our data suggest that uridylation-dependent decapping is mediated by the Lsm1-7 complex.

View Article: PubMed Central - PubMed

Affiliation: Sir William Dunn School of Pathology, University of Oxford, UK.

ABSTRACT
Both end structures of eukaryotic mRNAs, namely the 5' cap and 3' poly(A) tail, are necessary for transcript stability, and loss of either is sufficient to stimulate decay. mRNA turnover is classically thought to be initiated by deadenylation, as has been particularly well described in Saccharomyces cerevisiae. Here we describe two additional, parallel decay pathways in the fission yeast Schizosaccharomyces pombe. First, in fission yeast mRNA decapping is frequently independent of deadenylation. Second, Cid1-dependent uridylation of polyadenylated mRNAs, such as act1, hcn1 and urg1, seems to stimulate decapping as part of a novel mRNA turnover pathway. Accordingly, urg1 mRNA is stabilized in cid1Delta cells. Uridylation and deadenylation act redundantly to stimulate decapping, and our data suggest that uridylation-dependent decapping is mediated by the Lsm1-7 complex. As human cells contain Cid1 orthologs, uridylation may form the basis of a widespread, conserved mechanism of mRNA decay.

Show MeSH
Related in: MedlinePlus