The RNA helicase DDX39B regulates IL7R alternative splicing reducing the risk of Multiple Sclerosis
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE94730 | GEO | 2017/03/28
SECONDARY ACCESSION(S): PRJNA373878
REPOSITORIES: GEO
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Project description:Autoimmune disease is caused by environmental and genetic factors. Genetic factors associated with increased susceptibility to multiple sclerosis (MS), an autoimmune disease of the central nervous system, have been identified, but their mechanisms of action are incompletely understood.(Briggs, 2019) We previously established that the association between MS risk and the interleukin-7 receptor-a gene (IL7R) is mediated by alternative splicing of IL7R transcripts.(Gregory et al., 2007) This splicing is regulated by the RNA helicase DEAD Box Polypeptide 39B (DDX39B), which shows genetic and functional epistasis with IL7R in enhancing MS risk (Galarza-Munoz et al., 2017). Here we discover that DDX39B, which is also known by immunologists as BAT1 (Spies et al., 1989), impacts the expression of many genes likely to play roles in autoimmunity.(Allcock et al., 2001; Degli-Esposti et al., 1992) We show that DDX39B controls expression of Forkhead Box P3 (FOXP3), a master regulator of the development, maintenance and function of CD4+/CD25+ T regulatory cells(Georgiev et al., 2019; Josefowicz et al., 2012) and repressor of autoimmunity (Bennett et al., 2001; Brunkow et al., 2001; Chatila et al., 2000; Wildin et al., 2001). Splicing of FOXP3 introns, which belong to a new subclass of introns with C-rich polypyrimidine tracts, was exquisitely sensitive to DDX39B levels, making FOXP3 expression highly sensitive to the levels of this RNA helicase. Low DDX39B levels in primary human T regulatory cells lead to loss of regulatory gene expression and cytokine signatures and gain of effector ones. Given the importance of FOXP3 in autoimmunity, this work cements DDX39B as a critically important guardian of immune tolerance that can reduce autoimmune disease risk by regulating IL7R splicing and upregulating FOXP3.
2022-01-20 | GSE145773 | GEO
Project description:Dead-box RNA helicases are crucial in mRNA processing, specifically in RNA splicing. Our previous work has shown that DDX39B is responsible for regulating the splicing of IL7R exon 6 and several FOXP3 introns, which rely on DDX39B's helicase and ATPase activities, respectively [this is not accurate since exon 6 also must require the ATPase activity, which is required for helicase activity]. In this study, we aimed to investigate whether DDX39A, a highly homologous paralog of DDX39B, plays a similar role in regulating alternative RNA splicing. We find that DDX39A and DDX39B have significant redundancy in their gene targets, however, DDX39A is incapable of complementing defective splicing of IL7R exon 6 when DDX39B is knockdown. Conversely, overexpressing DDX39A can rescue FOXP3 intron 11 splicing under DDX39B-depleted conditions. In this work we also confirm that introns containing C-rich/U-poor polypyrimidine tract are very sensitive to DDX39B levels. We also observed that cassette exons with C-rich/U-poor py tracts in upstream introns were also sensitive to DDX39B levels and were skipped more upon depletion of DDX39B, but not DDX39A. Among the introns retained more upon DDX39A and DDX39B depletion were DDX39A and DDX39B intron 6, which depend on DDX39A and DDX39B levels, respectively. Therefore, we identified an autoregulatory mechanism through which DDX39A and DDX39B control their respective expression. This study presents evidence that while DDX39A and DDX39B differentially impact certain RNA splicing events, they have many shared targets.
2024-05-29 | GSE253261 | GEO
Project description:Multiple RNA processing events including transcription, mRNA splicing and export are delicately coordinated by the TREX complex. As one of the essential subunits, DDX39B couples the splicing and export machineries by recruiting ALYREF onto mRNA. In this study, we further explore the functions of DDX39B in handling damaged DNA, and unexpectedly find that DDX39B facilitates DNA repair by homologous recombination through upregulating BRCA1. Specifically, DDX39B binds to and stabilizes BRCA1 mRNA. DDX39B ensures ssDNA formation and RAD51 accumulation at DSB sites by maintaining BRCA1 levels. Without DDX39B being present, ovarian cancer cells exhibit hypersensitivity to DNA-damaging chemotherapeutic agents like platinum or PARPi. Moreover, DDX39B-deficient mice show embryonic lethality or developmental retardation, highly reminiscent of those lacking BRCA1. High DDX39B expression is correlated with worse survival in ovarian cancer patients. Thus, DDX39B suppression represents a rational approach for enhancing the efficacy of chemotherapy in BRCA1-proficient ovarian cancers.
2020-08-21 | GSE156543 | GEO
Project description:Non-scheduled R loops represent a major source of DNA damage and replication stress. Cells have different ways to prevent R loop accumulation. One mechanism relies on the conserved THO complex in association with co-transcriptional RNA processing factors including the RNA-dependent ATPase UAP56/DDX39B and histone modifiers such as the SIN3 deacetylase in humans. We investigated the function of UAP56/DDX39B in R loop removal. We show that UAP56 depletion causes R loop accumulation, R loop-mediated genome instability and replication fork stalling. We demonstrate an RNA-DNA helicase activity in UAP56 and that its overexpression suppresses R loops and genome instability induced by depleting 5 different unrelated factors. UAP56/DDX39B localizes to active chromatin and prevents the accumulation of RNA-DNA hybrids over the entire genome. We propose that, in addition to its RNA processing role, UAP56/DDX39B is a key helicase required to eliminate harmful co-transcriptional RNA structures that otherwise would block transcription and replication.
2020-05-25 | GSE127979 | GEO
Project description:The RNA helicase DDX39B activates FOXP3 RNA splicing to control T regulatory cell fate
| PRJNA608194 | ENA
Project description:Multiple sclerosis (MS) is an autoimmune disorder where T cells attack neurons in the central nervous system (CNS) leading to demyelination and neurological deficits. A driver of increased MS risk is the soluble form of the interleukin-7 receptor alpha chain gene (sIL7R) produced by alternative splicing of IL7R exon 6. Here, we identified the RNA helicase DDX39B as a potent activator of this exon and consequently a repressor of sIL7R, and we found strong genetic association of DDX39B with MS risk. Indeed, we showed that a genetic variant in the 5' UTR of DDX39B reduces translation of DDX39B mRNAs and increases MS risk. Importantly, this DDX39B variant showed strong genetic and functional epistasis with allelic variants in IL7R exon 6. This study establishes the occurrence of biological epistasis in humans and provides mechanistic insight into the regulation of IL7R exon 6 splicing and its impact on MS risk.
| S-EPMC5456452 | biostudies-literature
Project description:Multiple sclerosis (MS) is a common demyelinating neurodegenerative disease with a strong genetic component. Previous studies have associated genetic variants in IL2RA and IL7R in the pathophysiology of the disease. In this study, we describe the association between IL2RA (rs2104286) and IL7R (rs6897932) in the Canadian population. Genotyping 1,978 MS patients and 830 controls failed to identify any significant association between these variants and disease risk. However, stratified analysis for family history of disease and disease course identified a trend towards association for IL2RA in patients without a family history (p?=?0.05; odds ratio?=?0.77) and a significant association between IL7R and patients who developed progressive MS (PrMS) (p?=?0.002; odds ratio?=?0.73). Although not statistically significant, the effect of IL2RA (rs2104286) in patients without a family history of MS indicates that the genetic components for familial and sporadic disease are perhaps distinct. This data suggests that the onset of sporadic disease is likely determined by a large number of variants of small effect, whereas MS in patients with a family history of disease is caused by a few deleterious variants. In addition, the significant association between PrMS and rs6897932 indicates that IL7R may not be disease-causing but a determinant of disease course. Further characterization of the effect of IL2RA and IL7R genetic variants in defined MS subtypes is warranted to evaluate the effect of these genes on specific clinical outcomes and to further elucidate the mechanisms of disease onset and progression.
| S-EPMC5094890 | biostudies-literature
Project description:Unwinding the roles of DEAD-box RNA helicases DDX39A and DDX39B in alternative RNA splicing
| PRJNA1064916 | ENA
Project description:ObjectiveTo investigate the association between IL7R rs6897932 and multiple sclerosis (MS) in southern Chinese people.MethodsIn total, 147 MS patients and 530 healthy controls were recruited according to the revised McDonald criteria. The TaqMan method was used for genotyping.ResultsWith genetic models, we can observe that the additive model, the dominant model, and the recessive model of IL7R rs6897932 were significantly associated with MS [additive model: p=0.032; dominant model (adjusted): p<0.001, OR=3.61 (95% CI 2.25-5.83); recessive model (adjusted): p<0.001, OR=6.80 (95% CI 3.49-13.89)].ConclusionOur results suggest that IL7R rs6897932 is associated with MS in a southern Chinese population. More and larger MS studies to explore the genetic risk factors of MS are warranted.
| S-EPMC9426677 | biostudies-literature
Project description:Genes associated with increased susceptibility to multiple sclerosis (MS) have been identified, but their functions are incompletely understood. One of these genes codes for the RNA helicase DExD/H-Box Polypeptide 39B (DDX39B), which shows genetic and functional epistasis with interleukin-7 receptor-α gene (IL7R) in MS-risk. Based on evolutionary and functional arguments, we postulated that DDX39B enhances immune tolerance thereby decreasing MS risk. Consistent with such a role we show that DDX39B controls the expression of many MS susceptibility genes and important immune-related genes. Among these we identified Forkhead Box P3 (FOXP3), which codes for the master transcriptional factor in CD4+/CD25+ T regulatory cells. DDX39B knockdown led to loss of immune-regulatory and gain of immune-effector expression signatures. Splicing of FOXP3 introns, which belong to a previously unrecognized type of introns with C-rich polypyrimidine tracts, was exquisitely sensitive to DDX39B levels. Given the importance of FOXP3 in autoimmunity, this work cements DDX39B as an important guardian of immune tolerance.
| S-EPMC10234631 | biostudies-literature