Adenosine‐rich elements present in the 5′‐untranslated region of PABP mRNA can selectively reduce the abundance and translation of CAT mRNAs in vivo

Melo, E. O.; Neto, Osvaldo P. de Melo; Sá, Cezar Martins de

doi:10.1016/s0014-5793(03)00620-3

Cited by 19 publications

(16 citation statements)

References 39 publications

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“…Our finding that yeast genes with a pre-AUG A ≥12 have a much reduced predicted protein synthesis rate (Figures 6) and ribosomal density (Figure 7) is consistent with the hypothesis that, while a pre-AUG A N may enhance translation by binding to translation initiation factors (Gallie and Tanguay 1994; Shirokikh and Spirin 2008), a long pre-AUG A N , by binding tightly to PABP, may repress translation by interfering with ribosomal scanning (Sachs et al 1987; Wu and Bag 1998; Bag 2001; Melo et al 2003a,b; Patel et al 2005; Ma et al 2006; Patel and Bag 2006). This hypothesis would predict that removing PABP would remove its inhibitory effect on mRNA with long pre-AUG A N .…”

Section: Discussionsupporting

confidence: 80%

“…While there is empirical evidence that mammalian PABP expression may be autoregulated by PABP binding to the pre-AUG A N of its own mRNA (Wu and Bag 1998; Bag 2001; Ma et al 2003a,b, 2006; Patel et al 2005; Patel and Bag 2006; Bag and Bhattacharjee 2010), there is no evidence that Pab1p abundance in yeast is autoregulated. Pab1p abundance is high, being the top 39th among the 3841 yeast genes with characterized protein abundance (Ghaemmaghami et al 2003).…”

Section: Discussionmentioning

confidence: 99%

“…While pre-AUG A N may improve translation efficiency, a few studies (Wu and Bag 1998; Bag 2001; Melo et al 2003a,b; Patel et al 2005; Ma et al 2006; Patel and Bag 2006; Bag and Bhattacharjee 2010) suggest an inhibitory effect of PABP when it binds to a long pre-AUG A N and presumably interferes with the scanning mechanism of translation initiation. The binding site of Pab1p in the yeast is about 12 consecutive A nucleotides, with the binding affinity decreasing rapidly with shorter poly(A) until 8, below which there is little affinity (Sachs et al 1987).…”

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confidence: 99%

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Translation Initiation: A Regulatory Role for Poly(A) Tracts in Front of the AUG Codon in Saccharomyces cerevisiae

et al. 2011

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The 5′-UTR serves as the loading dock for ribosomes during translation initiation and is the key site for translation regulation. Many genes in the yeast Saccharomyces cerevisiae contain poly(A) tracts in their 5′-UTRs. We studied these pre-AUG poly(A) tracts in a set of 3274 recently identified 5′-UTRs in the yeast to characterize their effect on in vivo protein abundance, ribosomal density, and protein synthesis rate in the yeast. The protein abundance and the protein synthesis rate increase with the length of the poly(A), but exhibit a dramatic decrease when the poly(A) length is ≥12. The ribosomal density also reaches the lowest level when the poly(A) length is ≥12. This supports the hypothesis that a pre-AUG poly(A) tract can bind to translation initiation factors to enhance translation initiation, but a long (≥12) pre-AUG poly(A) tract will bind to Pab1p, whose binding size is 12 consecutive A residues in yeast, resulting in repression of translation. The hypothesis explains why a long pre-AUG poly(A) leads to more efficient translation initiation than a short one when PABP is absent, and why pre-AUG poly(A) is short in the early genes but long in the late genes of vaccinia virus.

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Section: Discussionsupporting

confidence: 80%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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Translation Initiation: A Regulatory Role for Poly(A) Tracts in Front of the AUG Codon in Saccharomyces cerevisiae

et al. 2011

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“…For instance, the presence of hexamer AAAAAU, which matches the binding motif of PABPC1 (Paz et al , ), attenuated TE significantly (adjusted P = 6.4e‐04). Interestingly, although PABPC1, a cytoplasmic poly(A) binding protein, typically binds to 3ʹ poly(A) tails of eukaryotic mRNAs, it has been shown that PABPC1 binding to an A‐rich elements in its own 5ʹUTR could inhibit its translation (de Melo Neto et al , ; Melo et al , ). To substantiate our findings on other hexamer motifs, we chose two hexamers (AAUCCC and CAAGAU) for validation using reporter assays (Materials and Methods).…”

Section: Resultsmentioning

confidence: 99%

Pervasive isoform‐specific translational regulation via alternative transcription start sites in mammals

Wang

Hou

Quedenau

et al. 2016

Molecular Systems Biology

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Transcription initiated at alternative sites can produce mRNA isoforms with different 5ʹUTRs, which are potentially subjected to differential translational regulation. However, the prevalence of such isoform‐specific translational control across mammalian genomes is currently unknown. By combining polysome profiling with high‐throughput mRNA 5ʹ end sequencing, we directly measured the translational status of mRNA isoforms with distinct start sites. Among 9,951 genes expressed in mouse fibroblasts, we identified 4,153 showed significant initiation at multiple sites, of which 745 genes exhibited significant isoform‐divergent translation. Systematic analyses of the isoform‐specific translation revealed that isoforms with longer 5ʹUTRs tended to translate less efficiently. Further investigation of cis‐elements within 5ʹUTRs not only provided novel insights into the regulation by known sequence features, but also led to the discovery of novel regulatory sequence motifs. Quantitative models integrating all these features explained over half of the variance in the observed isoform‐divergent translation. Overall, our study demonstrated the extensive translational regulation by usage of alternative transcription start sites and offered comprehensive understanding of translational regulation by diverse sequence features embedded in 5ʹUTRs.

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“…7D). The tethered strategy has also been used by us to specifically investigate reduction in CAT mRNA abundance as well as translation in 293 cells mediated by PABP binding to its 5Ј-UTR (48). Full-length PABP fused to MS2, like the MS2/C terminus fusions described above, despite reducing the expression of the CAT construct MSC-91, does not affect the reporter mRNA levels.…”

Section: Fig 4 Cooperative Binding To Poly(a) By Pabp Does Not Requmentioning

confidence: 99%

Identification of a C-terminal Poly(A)-binding Protein (PABP)-PABP Interaction Domain

Melo

Dhália

et al. 2003

Journal of Biological Chemistry

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The poly(A)-binding protein (PABP), bound to the 3 poly(A) tail of eukaryotic mRNAs, plays critical roles in mRNA translation and stability. PABP autoregulates its synthesis by binding to a conserved A-rich sequence present in the 5-untranslated region of PABP mRNA and repressing its translation. PABP is composed of two parts: the highly conserved N terminus, containing 4 RNA recognition motifs (RRMs) responsible for poly(A) and eIF4G binding; and the more variable C terminus, which includes the recently described PABC domain, and promotes intermolecular interaction between PABP molecules as well as cooperative binding to poly(A). Here we show that, in vitro, GST-PABP represses the translation of reporter mRNAs containing 20 or more A residues in their 5-untranslated regions and remains effective as a repressor when an A 61 tract is placed at different distances from the cap, up to 126 nucleotides. Deletion of the PABP C terminus, but not the PABC domain alone, significantly reduces its ability to inhibit translation when bound to sequences distal to the cap, but not to proximal ones. Moreover, cooperative binding by multiple PABP molecules to poly(A) requires the C terminus, but not the PABC domain. Further analysis using pull-down assays shows that the interaction between PABP molecules, mediated by the C terminus, does not require the PABC domain and is enhanced by the presence of RRM 4. In vivo, fusion proteins containing parts of the PABP C terminus fused to the viral coat protein MS2 have an enhanced ability to prevent the expression of chloramphenicol acetyltransferase reporter mRNAs containing the MS2 binding site at distal distances from the cap. Altogether, our results identify a proline-and glutamine-rich linker located between the RRMs and the PABC domain as being strictly required for PABP/PABP interaction, cooperative binding to poly(A) and enhanced translational repression of reporter mRNAs in vitro and in vivo.

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Adenosine‐rich elements present in the 5′‐untranslated region of PABP mRNA can selectively reduce the abundance and translation of CAT mRNAs in vivo

Cited by 19 publications

References 39 publications

Translation Initiation: A Regulatory Role for Poly(A) Tracts in Front of the AUG Codon in Saccharomyces cerevisiae

Translation Initiation: A Regulatory Role for Poly(A) Tracts in Front of the AUG Codon in Saccharomyces cerevisiae

Pervasive isoform‐specific translational regulation via alternative transcription start sites in mammals

Identification of a C-terminal Poly(A)-binding Protein (PABP)-PABP Interaction Domain

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