scholarly journals Non-invasive measurement of mRNA decay reveals translation initiation as the major determinant of mRNA stability

2017 ◽  
Author(s):  
Leon Y Chan ◽  
Christopher F Mugler ◽  
Stephanie Heinrich ◽  
Pascal Vallotton ◽  
Karsten Weis

AbstractThe cytoplasmic abundance of mRNAs is strictly controlled through a balance of production and degradation. Whereas the control of mRNA synthesis through transcription has been well characterized, less is known about the regulation of mRNA turnover, and a consensus model explaining the wide variations in mRNA decay rates remains elusive. Here, we combine non-invasive transcriptome-wide mRNA production and stability measurements with selective and acute perturbations to demonstrate that mRNA degradation is tightly coupled to the regulation of translation, and that a competition between translation initiation and mRNA decay -but not codon optimality or elongation- is the major determinant of mRNA stability in yeast. Our refined measurements also reveal a remarkably dynamic transcriptome with an average mRNA half-life of only 4.8 minutes - much shorter than previously thought. Furthermore, global mRNA destabilization by inhibition of translation initiation induces a dose-dependent formation of processing bodies in which mRNAs can decay over time.

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Leon Y Chan ◽  
Christopher F Mugler ◽  
Stephanie Heinrich ◽  
Pascal Vallotton ◽  
Karsten Weis

The cytoplasmic abundance of mRNAs is strictly controlled through a balance of production and degradation. Whereas the control of mRNA synthesis through transcription has been well characterized, less is known about the regulation of mRNA turnover, and a consensus model explaining the wide variations in mRNA decay rates remains elusive. Here, we combine non-invasive transcriptome-wide mRNA production and stability measurements with selective and acute perturbations to demonstrate that mRNA degradation is tightly coupled to the regulation of translation, and that a competition between translation initiation and mRNA decay -but not codon optimality or elongation- is the major determinant of mRNA stability in yeast. Our refined measurements also reveal a remarkably dynamic transcriptome with an average mRNA half-life of only 4.8 min - much shorter than previously thought. Furthermore, global mRNA destabilization by inhibition of translation initiation induces a dose-dependent formation of processing bodies in which mRNAs can decay over time.


1999 ◽  
Vol 19 (8) ◽  
pp. 5247-5256 ◽  
Author(s):  
David C. Schwartz ◽  
Roy Parker

ABSTRACT The turnover of most mRNAs in Saccharomyces cerevisiaebegins with deadenylation followed by decapping and 5′→3′ exonucleolytic digestion. An important question involves the mechanisms that allow particular mRNAs to exhibit different rates of both deadenylation and decapping. Since the cap structure plays a critical role in the assembly of translation initiation factors, we hypothesized that the status of the cytoplasmic cap binding complex would affect the rate of decapping. To test this hypothesis, we examined mRNA decay rates in yeast strains that were defective in several translation initiation factors that are part of the cap binding complex. These experiments yielded three significant observations. First, any mutation known to inhibit translation initiation also increased the rate of decapping. Second, decapping still occurred only after deadenylation, suggesting that the ability of the poly(A) tail to inhibit decapping does not require efficient translation of the transcript. Third, mutants with defects in translation initiation factors also showed an increase in the rate of deadenylation, suggesting that the rate of deadenylation may be controlled primarily by the translation status of the transcript. These results argue that the nature of the translation initiation complex is a critical factor in determining the mRNA half-life. This view also implies that some cis-acting sequences that modulate mRNA decay rate do so by affecting the translation status of the transcript.


Genome ◽  
2006 ◽  
Vol 49 (8) ◽  
pp. 894-899 ◽  
Author(s):  
Bessie W Kebaara ◽  
Lindsey E Nielsen ◽  
Kenneth W Nickerson ◽  
Audrey L Atkin

A method for determining mRNA half-lives in the polymorphic fungus Candida albicans is described. It employs growth in a defined medium, the inhibition of transcription with thiolutin (10–20 µg/mL), and quantitative Northern blotting. The method is effective for the A72, SC5314, and CAI-4 strains of C. albicans, and for mRNAs that have a wide variety of decay rates and steady-state abundances. The range of half-lives detected (from 4–168 min) shows that this method is effective for mRNAs with widely varying half-lives. The mRNA decay rates obtained are compared with those for orthologous mRNAs from Saccharomyces cerevisiae. This procedure should work for a broad range of C. albicans strains and can be adapted to other fungal species.Key words: comparative mRNA stability, ACT1, ADH1, EFG1, PGK1, 18S rRNA, mRNA decay.


2003 ◽  
Vol 185 (18) ◽  
pp. 5372-5379 ◽  
Author(s):  
Josh S. Sharp ◽  
David H. Bechhofer

ABSTRACT A 254-nucleotide model mRNA, designated ΔermC mRNA, was used to study the effects of translational signals and ribosome transit on mRNA decay in Bacillus subtilis. ΔermC mRNA features a strong ribosome-binding site (RBS) and a 62-amino-acid-encoding open reading frame, followed by a transcription terminator structure. Inactivation of the RBS or the start codon resulted in a fourfold decrease in the mRNA half-life, demonstrating the importance of ternary complex formation for mRNA stability. Data for the decay of ΔermC mRNAs with stop codons at positions increasingly proximal to the translational start site showed that actual translation—even the formation of the first peptide bond—was not important for stability. The half-life of an untranslated 3.2-kb ΔermC-lacZ fusion RNA was similar to that of a translated ΔermC-lacZ mRNA, indicating that the translation of even a longer RNA was not required for wild-type stability. The data are consistent with a model in which ribosome binding and the formation of the ternary complex interfere with a 5′-end-dependent activity, possibly a 5′-binding endonuclease, which is required for the initiation of mRNA decay. This model is supported by the finding that increasing the distance from the 5′ end to the start codon resulted in a 2.5-fold decrease in the mRNA half-life. These results underscore the importance of the 5′ end to mRNA stability in B. subtilis.


2018 ◽  
Vol 29 (8) ◽  
pp. 988-1002 ◽  
Author(s):  
Mei-Yan Qi ◽  
Jing-Wen Song ◽  
Zhuo Zhang ◽  
Shuang Huang ◽  
Qing Jing

Tristetraprolin (TTP) destabilizes AU-rich element (ARE)-containing mRNA by directly binding with their 3′UTR. P38 stimulation substantially increases ARE-mRNA stability, at least through repressing TTP. However, the mechanism by which P38 keeps TTP inactive has not been fully understood. TTP and ARE-mRNA localize to processing bodies (PBs), the mRNA granules associated with mRNA silencing. Here, we detected the influence of P38 on TTP localization within PBs and found that P38 regulates TTP localization within PBs. Through luciferase-based systems, we demonstrated that PBs depletion significantly increased ARE-mRNA stability inhibited by TTP. Additionally, we provided evidence that the microRNA-induced silencing complex (miRISC) core member Ago2 is required for TTP distribution within PBs. Importantly, the cooperation of TTP and Ago2 is a prerequisite for effective ARE-mRNA degradation. Moreover, Dcp1a and Dcp2 act downstream of Ago2 and TTP engaging in ARE-mRNA decay. Finally, we demonstrated that P38 activation represses the interaction between TTP and Ago2 due to TTP phosphorylation, which impairs TTP localization within PBs and ARE-mRNA degradation. Collectively, our study revealed a novel mechanism through which P38 activation repressed the cooperation of TTP with Ago2, thus ensuring that ARE-mRNA does not associate with PBs and remains stable.


2005 ◽  
Vol 25 (22) ◽  
pp. 9764-9772 ◽  
Author(s):  
Hudan Liu ◽  
Megerditch Kiledjian

ABSTRACT mRNA degradation occurs through distinct pathways, one primarily from the 5′ end of the mRNA and the second from the 3′ end. Decay from the 3′ end generates the m7GpppN cap dinucleotide, which is subsequently hydrolyzed to m7Gp and ppN in Saccharomyces cerevisiae by a scavenger decapping activity termed Dcs1p. Although Dcs1p functions in the last step of mRNA turnover, we demonstrate that its activity modulates earlier steps of mRNA decay. Disruption of the DCS1 gene manifests a threefold increase of the TIF51A mRNA half-life. Interestingly, the hydrolytic activity of Dcs1p was essential for the altered mRNA turnover, as Dcs1p, but not a catalytically inactive Dcs1p mutant, complemented the increased mRNA stability. Mechanistic analysis revealed that 5′ to 3′ exoribonucleolytic activity was impeded in the dcs1Δ strain, resulting in the accumulation of uncapped mRNA. These data define a new role for the Dcs1p scavenger decapping enzyme and demonstrate a novel mechanism whereby the final step in the 3′ mRNA decay pathway can influence 5′ to 3′ exoribonucleolytic activity.


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