Project description:A better understanding of the mechanisms for plant in response to abiotic stresses is key for the improvement of plant to resistant to the stresses. Much has been known for the regulation of gene expression in response to salt stress at transcriptional level, however, little is known at posttranscriptional level for this response. Recently, we identified that SKIP is a component of spliceosome and is necessary for the regulation of alternative splicing and mRNA maturation of clock genes. In this study, we observed that skip-1 is hypersensitive to salt stress. SKIP is necessary for the alternative splicing and mRNA maturation of several salt tolerance genes, e.g. NHX1, CBL1, P5CS1, RCI2A, and PAT10. Genome-wide analysis reveals that SKIP mediates the alternative splicing of many genes under salt stress condition, most of the new alternative splicing events in skip-1 is intron retention, which leads to the premature termination codon in their mRNA. SKIP also controls the alternative splicing by modulating the recognition or cleavage of 5' and 3' splice donor and acceptor sites under salt stress condition. Therefore, this study addresses a fundamental question on how the mRNA splicing machinery contributes to salt response at a posttranscriptional level. Totally six samples, two treatments and two genotypes, and each have two replicats.
Project description:A better understanding of the mechanisms for plant in response to abiotic stresses is key for the improvement of plant to resistant to the stresses. Much has been known for the regulation of gene expression in response to salt stress at transcriptional level, however, little is known at posttranscriptional level for this response. Recently, we identified that SKIP is a component of spliceosome and is necessary for the regulation of alternative splicing and mRNA maturation of clock genes. In this study, we observed that skip-1 is hypersensitive to salt stress. SKIP is necessary for the alternative splicing and mRNA maturation of several salt tolerance genes, e.g. NHX1, CBL1, P5CS1, RCI2A, and PAT10. Genome-wide analysis reveals that SKIP mediates the alternative splicing of many genes under salt stress condition, most of the new alternative splicing events in skip-1 is intron retention, which leads to the premature termination codon in their mRNA. SKIP also controls the alternative splicing by modulating the recognition or cleavage of 5' and 3' splice donor and acceptor sites under salt stress condition. Therefore, this study addresses a fundamental question on how the mRNA splicing machinery contributes to salt response at a posttranscriptional level.
Project description:Abscisic acid (ABA) plays a key role in plant development and responses to abiotic stress. A wide number of regulatory mechanisms on ABA perception and signaling are known, including transcriptional regulation and post-translational regulations; however, less to know about the post-transcriptional regulations. In this work, we have found that SKIP, a splicing factor in spliceosome, positively regulates ABA signal transduction. Mutation of SKIP, skip-1, confers ABA insensitive phenotype in seed germination, root growth, and ABA-responsive gene expression. Transformation of SKIP genomic DNA to skip-1 is able to recover its defects. SKIP binds to the pre-mRNA of genes in ABA signaling, such as PYL8, to regulate their splicing. The alternative splicing of PYL7, PYL8, ABF2, and ABI5 in ABA pathway is disrupted by skip-1, reducing the mRNA levels of them. The abnormal splicing of PP2Cs activates their transcription by skip-1, suggesting there is a feedback regulation for PP2Cs caused by skip-1. The down-regulation of PYL ABA receptors, ABF2 and ABI5 ABA response transcription factors, and the up-regulation of PP2Cs through alternative splicing reduce the plant responses to ABA in skip-1. SKIP is required for ABA-mediated genome-wide alternative splicing. ABA treatment enhances the novel splicing events in WT genome-widely. The novel alternative splicing events are increased by skip-1 in the absence and present of ABA. Our results first reveal a principle on how a splicing factor affects the ABA signaling.
Project description:Although pre-mRNA alternative splicing has been demonstrated to be a crucial layer of gene expression regulation in response to salt stress, the underlying mechanisms remain elusive. Through integrative studies of the singular ortholog of DGCR14 in Arabidopsis thaliana (AtDGCR14L), we discovered that AtDGCR14L plays an essential role in plant salt stress responses by maintaining the constitutively spliced and active isoforms of important stress- and/or ABA-responsive genes. We also identified the interaction between AtDGCR14L and spliceosome component U1-70k mediated by a highly conserved TWG motif in DGCR14, which is crucial for AtDGCR14L’s functions in salt stress responses. Moreover, we discovered the novel role of SWI3A, whose splicing is dependent on AtDGCR14L, in controlling salt stress tolerance. Collectively, these results revealed the central role of AtDGCR14L in linking plant salt-stress tolerance with pre-mRNA splicing mechanism. This work also provided new insights into the mechanism of 22q11.2 deletion-induced developmental disorders in humans.
Project description:Circadian clocks generate endogenous rhythms in most organisms from cyanobacteria to humans and facilitate entrainment to environmental diurnal cycles, thus conferring a fitness advantage. Both transcriptional and posttranslational mechanisms are prominent in the basic network architecture of circadian systems. Posttranscriptional regulation, including mRNA processing, is emerging as a critical step for the clock function. However, little is known about the molecular mechanisms linking RNA metabolism to the circadian clock network. Here we report that a conserved SNW/SKIP domain protein, SKIP, a splicing factor and component of the spliceosome, is involved in the posttranscriptional regulation of circadian clock genes in Arabidopsis. Mutation in SKIP lengthens the circadian period in a temperature sensitive manner, affects light input and the sensitivity of light resetting to the clock. SKIP physically interacts with the spliceosomal splicing factor SR45 and associates with the pre-mRNA of clock genes, such as PRR7 and PRR9, and is necessary for the regulation of their alternative splicing and mRNA maturation. Genome-wide investigations reveal that SKIP functions in regulating alternative splicing of many genes, presumably through modulating recognition or cleavage of 5' and 3' splicing site. Our study addresses a fundamental question on how the mRNA splicing machinery contributes to circadian clock functions at a posttranscriptional level. Our findings revealed that AtSKIP is a splicing factor and a component of spliceosome. To further investigate effects of mutation in SKIP on the genome-wide changes of alternative splicing, we performed ultra-highthroughput RNA sequencing, using 10-day old seedlings. Two biological replicates for both wild type (Col-0) and skip-2 were designed.
Project description:Salt stress caused by soil salination inhibits plant growth and development that result in reduction of crop yield and threaten the food security. Several spliceosome components are considered to modify salt stress responses in plants. However, the molecular basis of spliceosome proteins adjustment to salt stress is still unclear. Here we report that an Sm core protein SmEb is required for salt tolerance in Arabidopsis. In addition, SmEb controls alternative splicing of hundreds of pre-mRNA to participate in plant response to salt stress. Our results further reveal that SmEb takes effect on maintain proper ratio of two RCD1 splicing variants to adjust to H2O2 accumulation under salt stress. Together, our findings uncover that proper alternative splicing of pre-mRNAs governed by the spliceosome component SmEb is essential for plant salt stress responses. Salt stress caused by soil salination inhibits plant growth and development that result in reduction of crop yield and threaten the food security. Several spliceosome components are considered to modify salt stress responses in plants. However, the molecular basis of spliceosome proteins adjustment to salt stress is still unclear. Here we report that an Sm core protein SmEb is required for salt tolerance in Arabidopsis. In addition, SmEb controls alternative splicing of hundreds of pre-mRNA to participate in plant response to salt stress. Our results further reveal that SmEb takes effect on maintain proper ratio of two RCD1 splicing variants to adjust to H2O2 accumulation under salt stress. Together, our findings uncover that proper alternative splicing of pre-mRNAs governed by the spliceosome component SmEb is essential for plant salt stress responses.
Project description:Circadian clocks generate endogenous rhythms in most organisms from cyanobacteria to humans and facilitate entrainment to environmental diurnal cycles, thus conferring a fitness advantage. Both transcriptional and posttranslational mechanisms are prominent in the basic network architecture of circadian systems. Posttranscriptional regulation, including mRNA processing, is emerging as a critical step for the clock function. However, little is known about the molecular mechanisms linking RNA metabolism to the circadian clock network. Here we report that a conserved SNW/SKIP domain protein, SKIP, a splicing factor and component of the spliceosome, is involved in the posttranscriptional regulation of circadian clock genes in Arabidopsis. Mutation in SKIP lengthens the circadian period in a temperature sensitive manner, affects light input and the sensitivity of light resetting to the clock. SKIP physically interacts with the spliceosomal splicing factor SR45 and associates with the pre-mRNA of clock genes, such as PRR7 and PRR9, and is necessary for the regulation of their alternative splicing and mRNA maturation. Genome-wide investigations reveal that SKIP functions in regulating alternative splicing of many genes, presumably through modulating recognition or cleavage of 5' and 3' splicing site. Our study addresses a fundamental question on how the mRNA splicing machinery contributes to circadian clock functions at a posttranscriptional level.
Project description:this study discovered unique glycoprotein resources responsible for plant salt stress tolerance and suggested crucial roles of Nthis study discovered unique glycoprotein resources responsible for plant salt stress tolerance and suggested crucial roles of N-glycans in regulating salt responsive protein expression in Arabidopsis.-glycans in regulating salt responsive protein expression in Arabidopsis.
Project description:Alternative splicing generates functional diversity in higher organisms through alternative first and last exons, skipped and included exons, intron retentions and alternative donor and acceptor sites. In large-scale microarray studies in human and mouse, emphasis so far has been placed on exon-skip events, leaving the prevalence and importance of other splice types largely unexplored. Using a new human splice variant database and a genome-wide microarray to probes thousands of splice events of each type, we measured differential expression of splice types across 6 pairs of diverse cell lines and validated the database annotation process. Results suggest that splicing in human is more complex than simple exon skip events, which account for a minority of splicing differences. The relative frequency of differential expression of the splice types correlates with what is found by our annotation efforts. In conclusion, alternative splicing in human cells is considerably more complex than the canonical example of the exon-skip. The complementary approaches of genome-wide annotation of alternative splicing in human and design of genome-wide splicing microarrays to measure differential splicing in biological samples provide a powerful high-throughput tool to study the role of alternative splicing in human biology. Keywords: alternative splicing