Project description:The SMA disease results from deletions or mutations in the “survival of motor neuron” (SMN1) gene. The SMN protein plays an essential role in the biogenesis of spliceosomal snRNPs but the link between a defect in this process and specific splicing inhibition is not known. Here, we report the construction of a temperature degron (td) allele of the S. pombe SMN protein and show that its depletion at 37°C affects snRNPs stability and splicing. In addition, the function of the tdSMN allele in snRNPs assembly is affected already at 25°C suggesting a deleterious effect of the tag at this temperature. Remarkably, using S. pombe tiling arrays and RT-PCR validation tests, we report that splicing is altered differentially in the tdSMN cells at permissive temperature. Our results suggest that the defects observed in tdSMN fission yeast cells mimic splicing deficits observed in SMN-deficient metazoan cells.
Project description:Here, we report the high-throughput profiling of histone modification (H3K9me2) in fission yeast Schizosaccharomyces pombe. We generated genome-wide H3K9me2 maps of fission yeast mutants in swo1-26 (temperature sensitive, ts) cells at 25℃ and 37℃. We find that H3K9me2 enrichment at heterochromatin regions, especially at the mating-type locus and subtelomeres, is compromised, suggesting heterochromatin assembly defects.
Project description:During the early steps of snRNP biogenesis, the Survival of Motor Neuron (SMN) complex acts together with the methylosome, an entity formed by the pICln protein, WD45 and the PRMT5 methyltransferase. To expand our understanding of pICln and SMN functional relationships in vivo, we performed a genetic analysis of an uncharacterized S. pombe pICLn homologue. Although not essential, the S. pombe ICln protein is important for optimal yeast cell growth. The human pICln gene complements the icln∆ slow growth phenotype demonstrating that the identified SpICln sequence represents the bona fide human homolog. Consistent with the role inferred for human pICln using in vitro experiments, we found that the SpICln protein is required for optimal production of the spliceosomal snRNPs and for efficient splicing in vivo. Genetic interaction approaches demonstrate furthermore that modulation of ICln activity is unable to compensate for defects induced by SMN mutations, and reciprocally. Using a genome-wide approach and RT-PCR validation tests, we show also that splicing is altered differentially in icln∆ cells. Our data are consistent with the emerging view that splice site selection and spliceosome kinetics is highly dependent on the concentration of core spliceosomal components.
Project description:During the early steps of snRNP biogenesis, the Survival of Motor Neuron (SMN) complex acts together with the methylosome, an entity formed by the pICln protein, WD45 and the PRMT5 methyltransferase. To expand our understanding of pICln and SMN functional relationships in vivo, we performed a genetic analysis of an uncharacterized S. pombe pICLn homologue. Although not essential, the S. pombe ICln protein is important for optimal yeast cell growth. The human pICln gene complements the iclnM-bM-^HM-^F slow growth phenotype demonstrating that the identified SpICln sequence represents the bona fide human homolog. Consistent with the role inferred for human pICln using in vitro experiments, we found that the SpICln protein is required for optimal production of the spliceosomal snRNPs and for efficient splicing in vivo. Genetic interaction approaches demonstrate furthermore that modulation of ICln activity is unable to compensate for defects induced by SMN mutations, and reciprocally. Using a genome-wide approach and RT-PCR validation tests, we show also that splicing is altered differentially in iclnM-bM-^HM-^F cells. Our data are consistent with the emerging view that splice site selection and spliceosome kinetics is highly dependent on the concentration of core spliceosomal components. RNA from M-NM-^TIcln mutant (2 replicates) vs RNA from wild type cells (2 replicates)
Project description:Meiosis is a specialized cell division that generates gametes, such as eggs and sperm. Errors in meiosis result in miscarriages and are the leading cause of birth defects, however the molecular origins of these defects remain unknown. Studies in model organisms are beginning to identify the genes and pathways important for meiosis, but the parts list is still poorly defined. Here we present a comprehensive catalogue of genes required for meiosis in the fission yeast, Schizosaccharomyces pombe. Our genome-wide functional screen surveyed all non-essential genes for roles in chromosome segregation and spore formation. Novel genes required at distinct stages of the meiotic chromosome segregation and differentiation programme were identified. Preliminary characterization implicated three of these genes in centrosome/spindle pole body function, centromere and cohesion function. Our findings represent a near-complete parts list of genes required for meiosis in fission yeast, providing a valuable resource to advance our molecular understanding of meiosis.
Project description:Interconnections between RNA-processing pathways revealed by a sequencing-based genetic screen for pre-mRNA splicing mutants in fission yeast