Project description:Using genetic mutations to study protein functions in vivo is a central paradigm of modern biology. Single-domain camelid antibodies generated against GFP have been engineered as nanobodies or GFP-binding proteins (GBPs) that can bind GFP as well as some GFP variants with high affinity and selectivity. In this study, we have used GBP-mCherry fusion protein as a tool to perturb the natural functions of a few kinetochore proteins in the fission yeast Schizosaccharomyces pombe. We found that cells simultaneously expressing GBP-mCherry and the GFP-tagged inner kinetochore protein Cnp1 are sensitive to high temperature and microtubule drug thiabendazole (TBZ). In addition, kinetochore-targeted GBP-mCherry by a few major kinetochore proteins with GFP tags causes defects in faithful chromosome segregation. Thus, this setting compromises the functions of kinetochores and renders cells to behave like conditional mutants. Our study highlights the potential of using GBP as a general tool to perturb the function of some GFP-tagged proteins in vivo with the objective of understanding their functional relevance to certain physiological processes, not only in yeasts, but also potentially in other model systems.
Project description:TOP2B is involved in transcriptional initiation in response to nuclear hormone ligands and plays a role in transcriptional elongation. Whole genome TOP2B ChIP-seq was carried out on human MCF7 cells in the presence and absence of the nuclear hormone estradiol. Three peak calling methods were used and the peaks identified by at least two methods were analyzed further. Approximately half of the peaks fell either within a gene or within 5Kb of a transcription start site. The coincidence of TOP2B peaks and gene promoters was analyzed; TOP2B peaks were less frequently associated with promoters in estradiol treated than in control cells, suggesting a role of TOP2B in repression of transcription or a transient role in estradiol induced transcriptional changes. Whole genome TOP2B ChIP-seq was carried out on human MCF7 cells in the presence (30 mins exposure) and absence of the nuclear hormone estradiol. "Input" control samples were also sequenced for background detection and comparison.
Project description:TOP2B is involved in transcriptional initiation in response to nuclear hormone ligands and plays a role in transcriptional elongation. Whole genome TOP2B ChIP-seq was carried out on human MCF7 cells in the presence and absence of the nuclear hormone estradiol. Three peak calling methods were used and the peaks identified by at least two methods were analyzed further. Approximately half of the peaks fell either within a gene or within 5Kb of a transcription start site. The coincidence of TOP2B peaks and gene promoters was analyzed; TOP2B peaks were less frequently associated with promoters in estradiol treated than in control cells, suggesting a role of TOP2B in repression of transcription or a transient role in estradiol induced transcriptional changes.
Project description:ChIP-chip analyses of H3K9me2 (in WT, erh1â??, mmi1â?? and ccr4â??), Erh1-GFP (in WT and mmi1â??) and CFP-Mmi1 (in WT) H3K9me2: WT vs erh1â??, WT vs mmi1â?? and WT vs ccr4â??; Erh1-GFP: WT vs mmi1â??; CFP-Mmi1 in WT, Biological replicates: 2
Project description:Eukaryotic protein kinases are key molecules mediating signal transduction that play a pivotal role in the regulation of various biological processes, including cell cycle progression, cellular morphogenesis, development, and cellular response to environmental changes. A total of 106 eukaryotic protein kinase catalytic-domain-containing proteins have been found in the entire fission yeast genome, 44% (or 64%) of which possess orthologues (or nearest homologues) in humans, based on sequence similarity within catalytic domains. Systematic deletion analysis of all putative protein kinase-encoding genes have revealed that 17 out of 106 were essential for viability, including three previously uncharacterized putative protein kinases. Although the remaining 89 protein kinase mutants were able to form colonies under optimal growth conditions, 46% of the mutants exhibited hypersensitivity to at least 1 of the 17 different stress factors tested. Phenotypic assessment of these mutants allowed us to arrange kinases into functional groups. Based on the results of this assay, we propose also the existence of four major signaling pathways that are involved in the response to 17 stresses tested. Microarray analysis demonstrated a significant correlation between the expression signature and growth phenotype of kinase mutants tested. Our complete microarray data sets are available at http://giscompute.gis.a-star.edu.sg/~gisljh/kinome.
