Poly(A), poly(A) binding protein and the regulation of mRNA stability

Bernstein, Philip; Ross, Jeffrey

doi:10.1016/0968-0004(89)90011-x

Cited by 332 publications

(145 citation statements)

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“…Shortening of the poly(A) tail is the initial step to trigger mRNA for decay in two major mRNA degradation pathways in eukaryotic cells (Bernstein and Ross, 1989;Peltz et al, 1991;Decker and Parker, 1994;Beelman and Parker, 1995). In one pathway, the deadenylated mRNA is degraded by a cytoplasmic protein complex, the exosome, consisting of a number of exonucleases with 3Ј-5Ј activity (Butler, 2002).…”

Section: Introductionmentioning

confidence: 99%

Ataxin-2 Interacts with the DEAD/H-Box RNA Helicase DDX6 and Interferes with P-Bodies and Stress Granules

Nonhoff

Ralser

Welzel

et al. 2007

MBoC

312

320

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Tight control of translation is fundamental for eukaryotic cells, and deregulation of proteins implicated contributes to numerous human diseases. The neurodegenerative disorder spinocerebellar ataxia type 2 is caused by a trinucleotide expansion in the SCA2 gene encoding a lengthened polyglutamine stretch in the gene product ataxin-2, which seems to be implicated in cellular RNA-processing pathways and translational regulation. Here, we substantiate a function of ataxin-2 in such pathways by demonstrating that ataxin-2 interacts with the DEAD/H-box RNA helicase DDX6, a component of P-bodies and stress granules, representing cellular structures of mRNA triage. We discovered that altered ataxin-2 levels interfere with the assembly of stress granules and cellular P-body structures. Moreover, ataxin-2 regulates the intracellular concentration of its interaction partner, the poly(A)-binding protein, another stress granule component and a key factor for translational control. Thus, our data imply that the cellular ataxin-2 concentration is important for the assembly of stress granules and P-bodies, which are main compartments for regulating and controlling mRNA degradation, stability, and translation. INTRODUCTIONAn essential step in the control of global gene expression in eukaryotes is the regulation of mRNA translation and degradation. Shortening of the poly(A) tail is the initial step to trigger mRNA for decay in two major mRNA degradation pathways in eukaryotic cells (Bernstein and Ross, 1989;Peltz et al., 1991;Decker and Parker, 1994;Beelman and Parker, 1995). In one pathway, the deadenylated mRNA is degraded by a cytoplasmic protein complex, the exosome, consisting of a number of exonucleases with 3Ј-5Ј activity (Butler, 2002). In the other pathway, shortening of the poly(A) tail leads to the removal of the cap structure of the mRNA by the decapping proteins DCP1 and DCP2 facilitating 5Ј-3Ј degradation of the mRNA through the exoribonuclease XRN1 (Beelman and Parker, 1995;Butler, 2002). These proteins colocalize in discrete cytoplasmic foci in mammalian cells, termed processing bodies or P-bodies (also known as DCP1-or GW182-bodies), indicating that mRNA decay is restricted to distinct cytoplasmic compartments in mammalian cells (van Dijk et al., 2002;Cougot et al., 2004). The human protein CCR4, which is involved in mRNA deadenylation, the decapping stimulating LSm proteins LSm1-7, the DEAD/Hbox RNA helicase DDX6 (also known as RCK/p54), GW182, and Ge-1 are components of P-bodies (Bouveret et al., 2000;Eystathioy et al., 2002;Ingelfinger et al., 2002; LykkeAndersen, 2002;Cougot et al., 2004;Yu et al., 2005). Moreover, the RNA-associated protein 55, hEDC3, Hedls as well as factors of the RISC complex localize to P-bodies in mammalian cells (Fenger-Gron et al., 2005;Liu et al., 2005;Sen and Blau, 2005;Yang et al., 2006). P-bodies represent dynamic structures that are in an equilibrium with polysomes and contain nontranslating mRNA . Remarkably, recent work demonstrated that mRNA molecules entering P-bodies can a...

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Section: Introductionmentioning

confidence: 99%

Ataxin-2 Interacts with the DEAD/H-Box RNA Helicase DDX6 and Interferes with P-Bodies and Stress Granules

Nonhoff

Ralser

Welzel

et al. 2007

MBoC

312

320

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“…The mechanism of regulated turnover of mammalian mRNA, however, is largely unknown. Terminal structures, namely, the 5Ј cap and 3Ј poly(A) tail, serve as general stabilizing elements found on most mRNAs (7,14). Several internal sequences, such as an AU-rich element (10) or nonsense codons (5), which functionally shorten the half-lives (t 1/2 ) of mRNAs have been identified.…”

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confidence: 99%

“…The tail is a dynamic structure which serves as a mediator through which several important cellular processes including the initiation of translation (31), nucleocytoplasmic transport (18), and mRNA stability (7), are regulated. Most mRNAs are rapidly degraded following deadenylation of their 3Ј ends to approximately 30 adenylate residues (8,21,27,34).…”

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confidence: 99%

The Poly(A) Tail Inhibits the Assembly of a 3′-to-5′ Exonuclease in an In Vitro RNA Stability System

Ford

Bagga

Wilusz

1997

Molecular and Cellular Biology

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We have developed an in vitro system which faithfully reproduces several aspects of general mRNA stability. Poly(A) ؊ RNAs were rapidly and efficiently degraded in this system with no detectable intermediates by a highly processive 3 -to-5 exonuclease activity. The addition of a poly(A) tail of at least 30 bases, or a 3 histone stem-loop element, specifically stabilized these transcripts. Stabilization by poly(A) required the interaction of proteins with the poly(A) tail but did not apparently require a 3 OH or interaction with the 5 cap structure. Finally, movement of the poly(A) tract internal to the 3 end caused a loss of its ability to stabilize transcripts incubated in the system but did not affect its ability to interact with poly(A) binding proteins. The requirement for the poly(A) tail to be proximal to the 3 end indicates that it mediates RNA stability by blocking the assembly, but not the action, of an exonuclease involved in RNA degradation in vitro.The relative stability of RNA transcripts plays a key role in determining their steady-state levels as well as the rate of mRNA induction following a transcriptional stimulus (30). Mutations which affect transcript stability can have a very significant impact on regulated gene expression (26,33). The mechanism of regulated turnover of mammalian mRNA, however, is largely unknown. Terminal structures, namely, the 5Ј cap and 3Ј poly(A) tail, serve as general stabilizing elements found on most mRNAs (7,14). Several internal sequences, such as an AU-rich element (10) or nonsense codons (5), which functionally shorten the half-lives (t 1/2 ) of mRNAs have been identified. Furthermore, an internal element which stabilizes ␣ globin mRNA has recently been identified (38). Elucidating how the general and regulatory elements interact to determine the functional t 1/2 of mRNAs is vital to understanding the mechanism of RNA stability as a regulator of gene expression.The poly(A) tail, a posttranscriptional modification of the 3Ј end of all nonhistone mRNAs, is initially formed as a 150-to 200-base homopolymer (19) which assembles multiple molecules of a poly(A) binding protein (PABP) (13). The tail is a dynamic structure which serves as a mediator through which several important cellular processes including the initiation of translation (31), nucleocytoplasmic transport (18), and mRNA stability (7), are regulated. Most mRNAs are rapidly degraded following deadenylation of their 3Ј ends to approximately 30 adenylate residues (8,21,27,34). Many destabilizing elements appear to act by increasing the rate of deadenylation (11). The disruption of poly(A) tail function, therefore, appears to be the rate-limiting step in mRNA turnover. Following deadenylation, mRNA degradation can occur through a variety of exoand/or endonucleolytic pathways (4). The difficulty in identifying intermediates in mammalian mRNA turnover has significantly hindered attempts to probe further into mechanistic aspects of the turnover process.Mechanistic questions in mammalian systems are usually best ...

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“…However, we had previously observed that, even in the absence of ribozyme, there is a gradual reduction in A-SAA2 mRNA over time (data not shown). Such a reduction may be due to instability of the in vitro transcribed mRNA which does not have a 5 0 cap or a poly(A) tail to protect it from degradation by RNases [36,37]. We therefore designed kinetic experiments to test whether the reduction in mouse A-SAA2 mRNA over time was due to continued ribozyme activity rather than non-ribozyme mediated degradation.…”

Section: Resultsmentioning

confidence: 99%

Efficient In Vitro Cleavage of Mouse Acute Phase Serum Amyloid A mRNA Mediated by a Synthetic Hammerhead Ribozyme

Gaughan

Whitehead

1997

Scand J Immunol

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Gaughan DJ, Whitehead AS. Efficient In Vitro Cleavage of Mouse Acute Phase Serum Amyloid A mRNA Mediated by a Synthetic Hammerhead Ribozyme. Scand J Immunol 1997;46:51-58 The authors designed a hammerhead ribozyme, mRibSAA2, to cleave the mRNA for mouse acute phase serum amyloid A 2 (A-SAA2), a major acute phase protein that is massively induced during inflammation and that is deposited as fibrils during secondary amyloidosis. Using computer based secondary structure analysis, a GUC triplet (nucleotides 408-410) on a predicted stem loop in A-SAA2 mRNA was chosen as the target site for mRibSAA2. The ribozyme was tested in vitro and gave efficient and specific magnesium-dependent cleavage of mouse A-SAA2 mRNA into the expected fragments of 197 and 425 bases. The authors also demonstrated that the ribozyme retains cleavage activity over several hours. The use of the mRibSAA2 ribozyme as a research tool and possible therapeutic agent in mouse models of amyloidosis is discussed.

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Poly(A), poly(A) binding protein and the regulation of mRNA stability

Cited by 332 publications

References 28 publications

Ataxin-2 Interacts with the DEAD/H-Box RNA Helicase DDX6 and Interferes with P-Bodies and Stress Granules

Ataxin-2 Interacts with the DEAD/H-Box RNA Helicase DDX6 and Interferes with P-Bodies and Stress Granules

The Poly(A) Tail Inhibits the Assembly of a 3′-to-5′ Exonuclease in an In Vitro RNA Stability System

Efficient In Vitro Cleavage of Mouse Acute Phase Serum Amyloid A mRNA Mediated by a Synthetic Hammerhead Ribozyme

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