Project description:We report a chromosome engineering system for human neocentromere formation and characterize the first experimentally generated human neocentromere. Neocentromere formation promotes local H3K9me3 eviction and cohesin and RNA polymerase II recruitment. Long-term culture results in gradual maturation of the inner centromere.
Project description:We report a chromosome engineering system for human neocentromere formation and characterize the first experimentally generated human neocentromere. Neocentromere formation promotes local H3K9me3 eviction and cohesin and RNA polymerase II recruitment. Long-term culture results in gradual maturation of the inner centromere.
Project description:Human centromeres form primarily on ?-satellite DNA but sporadically arise de novo at naive ectopic loci, creating neocentromeres. Centromere inheritance is driven primarily by chromatin containing the histone H3 variant CENP-A. Here, we report a chromosome engineering system for neocentromere formation in human cells and characterize the first experimentally induced human neocentromere at a naive locus. The spontaneously formed neocentromere spans a gene-poor 100-kb domain enriched in histone H3 lysine 9 trimethylated (H3K9me3). Long-read sequencing revealed this neocentromere was formed by purely epigenetic means and assembly of a functional kinetochore correlated with CENP-A seeding, eviction of H3K9me3 and local accumulation of mitotic cohesin and RNA polymerase II. At formation, the young neocentromere showed markedly reduced chromosomal passenger complex (CPC) occupancy and poor sister chromatin cohesion. However, long-term tracking revealed increased CPC assembly and low-level transcription providing evidence for centromere maturation over time.
Project description:Gene expression changes during biofilm formation processes were investigated. The gene expression was compared at attachment, colony formation and maturation during biofilm formation. At the same time, the gene expressions were also compared with exponential phase and stationary phase in planktonic cells. The gene expression pattern at attachment and colony formation processes showed similar pattern with those in planktonic exponential phase, and the gene expression pattern at maturation process showed similar pattern with those in planktonic stationary phase. During the maturation process, metabolic activities of the cells in the biofilms decreased, and the genes involved in the anaerobic respiration and efflux pumps were induced. The analysis revealed that gene expression pattern was changed and the physiological states were changed dramatically during maturation process in the biofilms. Keywords: time course Affymetrix E. coli antisense genome array was used to compare the gene expression among biofilm formation processes (attachment, colony formation and maturation) and planktonic cells (exponential phase and stationary phase). All samples were grown in MOPS minimal media with 0.2% glucose at 37ºC. Biofilms were grown on glass surface in flow cells (1 x 4 x 40 mm), and samples were taken at 2 h, 24 h and 72 h. Planktonic cell were grown for 6 h (exponential phase) and 24 h (stationary phase). Experiments were repeated 3 times, which resulted in 3 replicates of 5 different samples.
Project description:Gene expression changes during biofilm formation processes were investigated. The gene expression was compared at attachment, colony formation and maturation during biofilm formation. At the same time, the gene expressions were also compared with exponential phase and stationary phase in planktonic cells. The gene expression pattern at attachment and colony formation processes showed similar pattern with those in planktonic exponential phase, and the gene expression pattern at maturation process showed similar pattern with those in planktonic stationary phase. During the maturation process, metabolic activities of the cells in the biofilms decreased, and the genes involved in the anaerobic respiration and efflux pumps were induced. The analysis revealed that gene expression pattern was changed and the physiological states were changed dramatically during maturation process in the biofilms. Keywords: time course