Project description:Humans co-existed and interbred with other hominins which later became extinct. These archaic hominins are known to us only through fossil records and for two cases, genome sequences. Here we engineer Neanderthal and Denisovan sequences into thousands of artificial genes to reconstruct the pre-mRNA processing patterns of these extinct populations. Of the 5,224 alleles tested in this massively parallel splicing reporter assay (MaPSy), we report 969 exonic splicing mutations (ESMs) that correspond to differences in exon recognition between extant and extinct hominins. Using MaPSy splicing variants, predicted splicing variants, and splicing quantitative trait loci, we show that splice-disrupting variants experienced greater purifying selection in anatomically modern humans than in Neanderthals. Adaptively introgressed variants were enriched for moderate effect splicing variants, consistent with positive selection for alternative spliced alleles following introgression. As particularly compelling examples, we characterized a novel tissue-specific alternative splicing variant at the adaptively introgressed innate immunity gene TLR1, as well as a novel Neanderthal introgressed alternative splicing variant in the gene HSPG2 that encodes perlecan. We further identified potentially pathogenic splicing variants found only in Neanderthals and Denisovans in genes related to sperm maturation and immunity. Finally, we found splicing variants that may contribute to variation among modern humans in total bilirubin, balding, hemoglobin levels, and lung capacity. Our findings provide novel insights into natural selection acting on splicing in human evolution and demonstrate how functional assays can be used to identify candidate causal variants underlying differences in gene regulation and phenotype.
Project description:Transplant-associated thrombotic microangiopathy (TA-TMA) is a life-threatening complication of allogeneic hematopoietic cell transplantation (HCT). We hypothesized that pre-transplant genetic susceptibility is evident in adult TA-TMA patients at the level of TMA-associated variants and further investigated the association of genetic variants with clinical outcomes. We studied 30 patients with TA-TMA at a median of 73 (9-540) post-transplant days, donors of 18/30 patients and 30 control non-TMA HCT recipients, without significant differences in transplant characteristics. Genomic DNA from pre-transplant peripheral blood was analyzed by targeted next generation sequencing for complement regulatory genes and ADAMTS13. Donors presented significantly lower frequency of rare variants (p=0.049) and variants in exonic/splicing/UTR regions (p=0.025), compared to TA-TMA patients. Controls also showed a significantly lower frequency of rare variants in ADAMTS13 (p=0.001), CD46 (p=0.002), CFH (p=0.010) and CFI (p=0.031). Pathogenic variants were found in ADAMTS13, CFH, CFI and CFB, while homozygous pathogenic variants in ADAMTS13 and CFB were evident in only 4 TA-TMA patients (p=0.038). Patients refractory to conventional treatment (70%) were significantly (p=0.045) enriched for variants in exonic/splicing/UTR regions compared to responders. Nineteen of 30 patients (63%) succumbed to transplant-related mortality, which was also associated with significantly (p=0.012) increased frequency of variants in exonic/splicing/UTR regions. In conclusion, increased incidence of pathogenic, rare and variants in exonic/splicing/UTR regions of TA-TMA patients suggests genetic susceptibility not evident in controls or donors. Notably, variants in exonic/splicing/UTR regions were associated with poor response and survival. Therefore, pre-transplant genomic screening may be useful to intensify monitoring and early intervention in high-risk patients.
Project description:It is estimated that 10-30% of disease-associated genetic variants affect splicing. Splicing variants may generate deleteriously altered gene product and are potential therapeutic targets. However, experimental diagnosis for splicing variants is time-consuming and reliable computational prediction tools have not been established, especially for the 3’ end of introns. The major challenge lies in the redundant and ill-defined branch site motif therein. Here, we carried out unbiased massively parallel splicing assays on 5,307 disease-associated variants overlapped with branch sites. We observed that 11.0% (455 out of 4,154 valid comparisons) of candidate variants showed a consistent pattern of altered splicing across four experimental replicates, among which 244 candidates (6.1%) presented more than two-fold changes in the use of noncanonical splice sites and these are named high-confidence (HC) significant candidates.
Project description:Using a high throughput splicing reporter assay, we tested 1,080 single nucleotide variants in POU1F1, a key transcription factor essential for pituitary development. Our saturation splicing effect map identifies 96 splice disruptive variants, including 14 synonymous variants, of which 8 were found in unrelated patients diagnosed with hypopituitarism.
Project description:How plants control the transition to flowering in response to ambient temperature is only beginning to be understood. In Arabidopsis thaliana, the MADS-box transcription factor genes FLOWERING LOCUS M (FLM) and SHORT VEGETATIVE PHASE (SVP) have key roles in this process. FLM is subject to temperature-dependent alternative splicing, producing two splice variants, FLM-M-NM-2 and FLM-M-NM-4, which compete for interaction with the floral repressor SVP. The SVP/FLM-M-NM-2 complex is predominately formed at low temperatures and prevents precocious flowering. In contrast, the competing SVP FLM-M-NM-4 complex is impaired in DNA binding and acts as a dominant negative activator of flowering at higher temperatures. Our results demonstrate the importance of temperature-dependent alternative splicing in modulating the timing of the floral transition in response to environmental change. ChIP-seq A. thaliana FLM (3 replicates for gFLM and 2 replicates for FLM splice variants)
Project description:In this dataset, we include the gene expression and exon splicing variants of two Ewing sarcoma cell lines (RDES and TC-32) after knockdown of the transcription factor SOX6 in order to obtain differentially expressed genes and different exon splicing variants.
Project description:Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including 7 recurrent variants in 30 individuals) and 6 individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function (LoF) of the Drosophila orthologs U2af50 and Prp19 led to lethality, abnormal mushroom body (MB) patterning, and social deficits, which were differentially rescued by wild-type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50-deficient flies. Upon reanalysis of negative clinical exomes followed by data sharing, we further identified 6 patients with NDD who carried RBFOX1 missense variants which, by in vitro testing, showed LoF. Our study implicates 3 splicing factors as NDD-causative genes and establishes a genetic network with hierarchy underlying human brain development and function.
Project description:Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including seven recurrent variants in 30 individuals) and six individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function of the Drosophila orthologs, U2af50 and Prp19, led to lethality, abnormal mushroom body (MB) patterning, and social deficits, differentially rescued by wild- type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50 deficient flies. Upon re-analysis of negative clinical exomes followed by data sharing, we further identified six NDD patients carrying RBFOX1 missense variants which, by in vitro testing, showed loss of function. Our study implicates three splicing factors as NDD causative genes and establishes a genetic network with hierarchy underlying human brain development and function.
Project description:Pre-mRNA splicing is a highly coordinated process. While its dysregulation has been linked to neurological deficits, our understanding of the underlying molecular and cellular mechanisms remains limited. We implicated pathogenic variants in U2AF2 and PRPF19, encoding spliceosome subunits in neurodevelopmental disorders (NDDs), by identifying 46 unrelated individuals with 23 de novo U2AF2 missense variants (including seven recurrent variants in 30 individuals) and six individuals with de novo PRPF19 variants. Eight U2AF2 variants dysregulated splicing of a model substrate. Neuritogenesis was reduced in human neurons differentiated from human pluripotent stem cells carrying two U2AF2 hyper-recurrent variants. Neural loss of function of the Drosophila orthologs, U2af50 and Prp19, led to lethality, abnormal mushroom body (MB) patterning, and social deficits, differentially rescued by wild- type and mutant U2AF2 or PRPF19. Transcriptome profiling revealed splicing substrates or effectors (including Rbfox1, a third splicing factor), which rescued MB defects in U2af50 deficient flies. Upon re-analysis of negative clinical exomes followed by data sharing, we further identified six NDD patients carrying RBFOX1 missense variants which, by in vitro testing, showed loss of function. Our study implicates three splicing factors as NDD causative genes and establishes a genetic network with hierarchy underlying human brain development and function.