Distinct Sets of Adjacent Heterogeneous Nuclear Ribonucleoprotein (hnRNP) A1/A2 Binding Sites Control 5′ Splice Site Selection in the hnRNP A1 mRNA Precursor

Hutchison, Stephen; LeBel, Catherine; Blanchette, Marco; Chabot, Benoît

doi:10.1074/jbc.m203633200

Cited by 80 publications

(70 citation statements)

References 45 publications

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“…We suggest that the ability of hnRNP A1 to dimerize facilitates formation of a loop structure in SMN2 premRNA that suppresses exon 7 splicing. This model is related to the original loop-out model proposed by Chabot and colleagues (12,13). In the SMN2 exon 7 case, however, one exonic and one intronic highaffinity hnRNP A1 site are necessary for looping, instead of two intronic sites in the case of hnRNP A1 exon 7b.…”

Section: Discussionmentioning

confidence: 99%

“…However, even in this case, both exonic and intronic A1 binding sites are necessary for full repression, perhaps reflecting cooperative interactions between A1 molecules. A third mechanism was elucidated by studies of alternative splicing of the hnRNP A1 transcript itself (12,13). The presence of hnRNP A1 binding sites in both introns surrounding alternative exon 7b is necessary for exclusion of this exon.…”

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confidence: 99%

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An intronic element contributes to splicing repression in spinal muscular atrophy

Kashima

Rao

Manley

2007

Proc. Natl. Acad. Sci. U.S.A.

116

109

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The neurodegenerative disease spinal muscular atrophy is caused by mutation of the survival motor neuron 1 (SMN1) gene. SMN2 is a nearly identical copy of SMN1 that is unable to prevent disease, because most SMN2 transcripts lack exon 7 and thus produce a nonfunctional protein. A key cause of inefficient SMN2 exon 7 splicing is a single nucleotide difference between SMN1 and SMN2 within exon 7. We previously provided evidence that this base change suppresses exon 7 splicing by creating an inhibitory element, a heterogeneous nuclear ribonucleoprotein (hnRNP) A1-dependent exonic splicing silencer. We now find that another rare nucleotide difference between SMN1 and SMN2, in intron 7, potentially creates a second SMN2-specific hnRNP A1 binding site. Remarkably, this single base change does indeed create a highaffinity hnRNP A1 binding site, and base substitutions that disrupt it restore exon 7 inclusion in vivo and prevent hnRNP A1 binding in vitro. We propose that interactions between hnRNP A1 molecules bound to the exonic and intronic sites cooperate to exclude exon 7 and discuss the significance of this exclusion with respect to SMN expression and splicing control more generally.alternative splicing ͉ exonic splicing silencer ͉ hnRNP A1 ͉ intronic splicing silencer A lternative splicing of mRNA precursors is an important mechanism that regulates gene expression and generates increased protein diversity from a limited number of genes. Indeed, expression of 70% or more of human genes is now estimated to involve alternative splicing (1, 2). In higher eukaryotes, alternative splicing plays an essential role in diverse cellular functions, contributing to such basic processes as cell growth, differentiation, and cell death (3, 4). Several types of cis-acting RNA elements and trans-acting protein factors help to regulate alternative splicing and do so by diverse mechanisms. In general, however, non-spliceosomal proteins that participate in regulating alternative splicing associate with regulatory elements in exons and/or introns. Serine/arginine-rich proteins (5) are typically involved in positive regulation of splicing, stimulating splicing by interacting with exonic splicing enhancer elements (ESEs) or intronic splicing enhancer elements. In contrast, negative regulation is promoted most frequently by heterogeneous nuclear ribonucleoproteins (hnRNPs) (6), which function by binding sequences known as exonic splicing silencers (ESSs) or intronic splicing silencers.Several hnRNP proteins have been identified as key splicing repressors. Among these, the abundant hnRNP A1 protein has been extensively characterized. The first hnRNP A1-dependent ESS was identified in studies of HIV tat exon 2 repression (7-9). This ESS was found to bind hnRNP A1, and mutations disrupting the ESS prevented hnRNP A1 binding and allowed enhanced exon 2 splicing. Several mechanisms have been proposed to explain hnRNP A1-mediated splicing repression. In one, hnRNP A1 binds to an ESS and through direct protein-protein interactions, recruits more ...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

An intronic element contributes to splicing repression in spinal muscular atrophy

Kashima

Rao

Manley

2007

Proc. Natl. Acad. Sci. U.S.A.

116

109

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“…1 Although hnRNPs were among the first eukaryotic RNA-binding proteins isolated, their role in vivo is complex and not fully delineated. hnRNP A1 is tightly associated with DNA polymerase II transcripts, and recent work has suggested that they may play an important role in the retention of introncontaining pre-mRNA within the nucleus (1) as well as already established roles in alternative splicing (2)(3)(4)(5)(6)(7)(8)(9)(10) and RNA transport (11)(12)(13)(14). In addition, hnRNP A1 has been demonstrated to bind purine-rich DNAs such as the human telomeric repeat (hTR) d(TTAGGG) n (15)(16)(17)(18) and mouse minisatellite (MN) repeat d(GGCAG) n (19).…”

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confidence: 99%

Structure-based Incorporation of 6-Methyl-8-(2-deoxy-β-ribofuranosyl)isoxanthopteridine into the Human Telomeric Repeat DNA as a Probe for UP1 Binding and Destabilization of G-tetrad Structures

Myers

Moore

Shamoo

2003

Journal of Biological Chemistry

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Heterogeneous ribonucleoprotein A1 (hnRNP A1) is an abundant nuclear protein that participates in RNA processing, alternative splicing, and chromosome maintenance. hnRNP A1 can be proteolyzed to unwinding protein (UP1), a 22.1-kDa protein that retains a high affinity for purine-rich single-stranded nucleic acids, including the human telomeric repeat (hTR) d(T-TAGGG) n . Using the structure of UP1 bound to hTR as a guide, we have incorporated the fluorescent guanine analog 6-MI at one of two positions within the DNA to facilitate binding studies. One is where 6-MI remains stacked with an adjacent purine, and another is where it becomes fully unstacked upon UP1 binding. The structures of both modified oligonucleotides complexed to UP1 were determined by x-ray crystallography to validate the efficacy of our design, and 6-MI has proven to be an excellent reporter molecule for single-stranded nucleic acid interactions in positions where there is a change in stacking environment upon complex formation. We have shown that UP1 affinity for d(TTAGGG) 2 is ϳ5 nM at 100 mM NaCl, pH 6.0, and our binding studies with d(TTAGG(6-MI)TTAGGG) show that binding is only modestly sensitive to salt and pH. UP1 also has a potent G-tetrad destabilizing activity that reduces the T m of the hTR sequence d(TAGGGT) 4 from 67.0°C to 36.1°C at physiological conditions (150 mM KCl, pH 7.0). Consistent with the structures determined by x-ray crystallography, UP1 is able to bind the hTR sequence in solution as a dimer and supports a model for hnRNP A1 binding to nucleic acids in arrays that may make a contiguous set of anti-parallel single-stranded nucleic acid binding clefts. These data suggest that seemingly disparate roles for hnRNP A1 in alternative splice site selection, RNA processing, RNA transport, and chromosome maintenance reflect its ability to bind a purine-rich consensus sequence (nYAGGn) and destabilize potentially deleterious G-tetrad structures.

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“…hnRNP A2 and B1 constitute the core, and are isomers of the same protein derived from the hnRNP A2/B1 gene. Thus, there are similarities in the sequence and function of these two proteins (7)(8)(9). Numerous studies have identified abnormally high expression of hnRNP A2/B1 in a variety of tumor types (10)(11)(12)(13)(14).…”

Section: Introductionmentioning

confidence: 99%

Insights into the roles of hnRNP A2/B1 and AXL in non-small cell lung cancer

Liu

Zhong

et al. 2015

Oncology Letters

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Abstract. Lung cancer has long been one of the most serious types of malignant tumor, and is associated with high incidence and mortality rates. Despite advancements in the comprehensive treatment of the disease, particularly with targeted therapeutic agents, there has been little improvement in the 5-year survival rates of patients. One of the leading causes of mortality in lung cancer is the lack of effective early diagnostic criteria. On this basis, the present study aimed to identify an index with potential in the early diagnosis and prognosis of lung cancer. The current study determined the expression of heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 and AXL proteins in non-small cell lung cancer (NSCLC) tumor samples, and performed prognostic analysis of the collected clinical data to identify any association. In addition, RNA interference was performed to silence the expression of hnRNP A2/B1, allowing evaluation of its molecular and cellular functions, and determination of the mechanism of hnRNP A2/B1 in NSCLC by means of AXL mediation. It was identified that the positive expression rate of hnRNP A2/B1 and AXL proteins were significantly higher in NSCLC compared with paracancerous lung tissues (P<0.05). Furthermore, the expression of hnRNP A2/B1 protein was correlated with the expression AXL. Thus, the expression of hnRNP A2/B1 and AXL protein are factors affecting prognosis in patients with NSCLC. Of these, hnRNP A2/B1 appears to be an independent risk factor.

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Distinct Sets of Adjacent Heterogeneous Nuclear Ribonucleoprotein (hnRNP) A1/A2 Binding Sites Control 5′ Splice Site Selection in the hnRNP A1 mRNA Precursor

Cited by 80 publications

References 45 publications

An intronic element contributes to splicing repression in spinal muscular atrophy

An intronic element contributes to splicing repression in spinal muscular atrophy

Structure-based Incorporation of 6-Methyl-8-(2-deoxy-β-ribofuranosyl)isoxanthopteridine into the Human Telomeric Repeat DNA as a Probe for UP1 Binding and Destabilization of G-tetrad Structures

Insights into the roles of hnRNP A2/B1 and AXL in non-small cell lung cancer

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