Project description:Patterns of alternative splicing during heat stress in Arabidopsis thaliana and Boechera depauperata indicate complex and species-specific interactions between differential expression and alternative splicing.
Project description:Alternative splicing caused by exposure of pollen to high temperatures leads to the generation of transcripts with pre-mature termination codon targeted for degradation or mRNAs putatively coding for truncated proteins with altered functions thereby controlling important cellular pathways including transport and localization, heat stress response, gene expression and various biosynthetic processes.
Project description:Although Sm-like proteins (LSMs) form the core of U6 RNPs and function in pre-mRNA splicing, little is known regarding their regulatory role in selection of splice sites, alternative splicing (AS) and splicing efficiency in eukaryotes. The Arabidopsis SAD1 locus encodes the LSM5 protein and was defined in a genetic screen for components that regulate the expression of stress-responsive gene. To further investigate regulatory role of the protein SAD1 in pre-mRNA splicing, we performed RNA sequencing (RNA-seq) to examine the changes of the global alternative splicing (AS) among the wildtype Arabidopsis plant (C24), the mutant plant (sad1) and the sad1-overexpressed plant (SAD1-OE). Our work not only provided novel insights into the regulatory role of SAD1 or LSM proteins in splicing, but also provided new cues to improving splicing efficiency and optimizing biological functions and screening the stress-resistant plant.
Project description:Vampire bats and snakes have taken thermosensation to the extreme by developing specialized systems for detecting infrared radiation. As such, these creatures provide a window into the molecular and genetic mechanisms underlying evolutionary tuning of thermoreceptors in a species or cell type specific manner. In each case, robust thermal sensitivity likely reflects specialized anatomical features of infrared sensing pit organs, as well as intrinsic heat sensitivity of trigeminal nerve fibers that innervate these structures. Here we show that vampire bats use a molecular strategy involving alternative splicing of the TRPV1 gene to generate a channel specifically within trigeminal ganglia that has a reduced thermal activation threshold. Selective expression of splicing factors in trigeminal, but not dorsal root ganglia, together with unique organization of the vampire bat TRPV1 gene underlies this mechanism of sensory adaptation. Comparative genomic analysis of the TRPV1 locus supports phylogenetic relationships within the proposed Pegasoferae clade of mammals. Gene expression measurements implicate a TRPV1 splice isoform as the heat-sensitive channel in vampire bats
Project description:The global impact of DNA methylation on alternative splicing is largely unknown. Using a genome-wide approach in wild-type and methylation-deficient embryonic stem cells, we found that DNA methylation can act both as an enhancer and as a silencer of splicing, and affects the splicing of more than 20% of alternative exons. These exons are characterized by distinct genetic and epigenetic signatures. Alternative splicing regulation of a subset of these exons can be explained by Heterochromatin protein 1 (HP1), which silences or enhances exon recognition in a position-dependent manner. We constructed an experimental system using site-specific targeting of a methylated/unmethylated gene, and demonstrate a direct causal relationship between DNA methylation and alternative splicing. HP1 regulates this geneM-bM-^@M-^Ys alternative splicing in a methylation-dependent manner by recruiting splicing factors to its methylated form. Our results demonstrate DNA methylation's significant global influence on mRNA splicing, and identify a specific mechanism of splicing regulation mediated by HP1. BS-seq on WT mouse ES cells (2 replicates), MNase-seq on WT and TKO cells (3 replicates), mRNA-seq on WT and TKO cells as well as HP1 knock-down cells (2 replicates for each sample)
Project description:Protein translation factors play crucial roles in a variety of stress responses. Here, we show that the eukaryotic elongation factor 1Bdelta (eEF1Bdelta) changes its structure and function from a translation factor into a heat shock response transcription factor by alternative splicing. While eEF1Bdelta is specifically localized in the cytoplasm, the long isoform of eEF1Bdelta (eEF1BdeltaL) is localized in the nucleus and induces heat shock element (HSE)-containing genes in cooperation with heat-shock transcription factor 1 (HSF1). Moreover, the N-terminal domain of eEF1BdeltaL binds with NF-E2-related factor 2 (Nrf2) and induces stress response heme oxygenase 1 (HO-1). Specific inhibition of eEF1BdeltaL with siRNA completely inhibits Nrf2-dependent HO-1 induction. In addition, eEF1BdeltaL directly binds to HSE oligo DNA in vitro and associates with HSE containing the HO-1-enhancer region in vivo. Thus, the transcriptional role of eEF1BdeltaL could provide new insights into the molecular mechanism of stress responses. We performed microarray analysis to compare the gene expression induced by eEF1Bdelta1 or eEF1BdeltaL overexpression. HEK293 cells transfected with expression plasmids encoding flag-tagged-eEF1Bdelta1 or eEF1BdeltaL protein
Project description:By targeted depletion of Cohesin (RAD21 subunit) or BRD4 alone or together, we have established that cohesin alone or with BRD4 regulates the alternative splicing of a large subset of genes under both physiological and heat shock conditions.
Project description:To investigate whether the observed changes in pre-mRNA splicing led to AtCYP18-1 depletion, we conducted RNA-sequencing to analyse the quantitative profiling of alternative splicing
Project description:How species with similar repertoires of protein coding genes differ so dramatically at the phenotypic level is poorly understood. From comparing the transcriptomes of multiple organs from vertebrate species spanning ~350 million years of evolution, we observe significant differences in alternative splicing complexity between the main vertebrate lineages, with the highest complexity in the primate lineage. Moreover, within as little as six million years, the splicing profiles of physiologically-equivalent organs have diverged to the extent that they are more strongly related to the identity of a species than they are to organ type. Most vertebrate species-specific splicing patterns are governed by the highly variable use of a largely conserved cis-regulatory code. However, a smaller number of pronounced species-dependent splicing changes are predicted to remodel interactions involving factors acting at multiple steps in gene regulation. These events are expected to further contribute to the dramatic diversification of alternative splicing as well as to other gene regulatory changes that contribute to phenotypic differences among vertebrate species.