Project description:Cytokinesis, the final stage of cell division, serves to physically separate daughter cells. In cultured naïve mouse embryonic stem cells cytokinesis lasts unusually long. Here, we describe a novel function for the kinesin-13 member KIF2A in this process. In genome-engineered mouse embryonic stem cells we find that KIF2A localises to spindle poles during metaphase and regulates spindle length in a manner consistent with its known role as microtubule minus-end depolymerase. By contrast, during cytokinesis we observe tight binding of KIF2A to intercellular bridge microtubules. At this stage KIF2A maintains microtubule length and number, and controls microtubule acetylation. We propose that the conversion of KIF2A from a depolymerase to a stabiliser is driven both by the inhibition of its ATPase activity, which increases lattice affinity, and a preference for compacted lattices. In turn, KIF2A might maintain the compacted microtubule state at the intercellular bridge, thereby dampening acetylation. As KIF2A depletion causes pluripotency problems and affects mRNA homeostasis our results furthermore indicate that KIF2A-mediated microtubule stabilisation prolongs cytokinesis to maintain pluripotency.
Project description:LC-MS/MS analysis of promoter pull-down assays with crude protein extracts from R. eutropha Re2058/pCB113, to identify putative transcriptional regulators involved in the expression control of PHA metabolism, specifically targeting phasin phaP1 and depolymerase phaZ3 and phaZ5 genes.
Project description:These experiments were performed to show a serogroup conversion of Vibrio cholerae from O1 to O139. For this purpose, V. cholerae O1 El Tor (A1552) was grown on crab shell fragments to induce natural competence for transformation. Purified DNA (4 ug each) from strain MO10, an O139 serogroup strain, was added after 24h and the cells were further grown for 24h. After detachment from the crab shell fragments, bacteria were poured into soft-agar and overlaid onto LB plates. Mukerjee's El Tor phage V (a gift of Dr. M.S. Islam) was dropped onto the surface of the bacteria containing soft-agar. The plaques formed by killing non-transformed A1552 cells possessed resistant clones which were picked and further selected for opaque morphotype and agglutination by O139-specific antiserum. Four clones were selected from each independent experiment and analyzed by microarray hybridization (BioPrime. Array CGH Genomic Labeling from Invitrogen). Two microarray replicates were done per clone. Strain Names: ApO139#2 / ApO139#4 / ApO139#6 / ApO139#8 are four clones analyzed after the first experiment; AIIpO139#3 / AIIpO139#4 / AIIpO139#5 / AIIpO139#6 are four clones analyzed after the second independent experiment. Two MA replicates for each clone were done. CGHs of A1552 versus MO10 are provided as control. Keywords: array CGH
Project description:These experiments were performed to show a serogroup conversion of Vibrio cholerae from O1 to 37. For this purpose, V. cholerae O1 El Tor (A1552) was grown on crab shell fragments to induce natural competence for transformation. Purified DNA (4 ug each) from strain ATCC25872, an O37 serogroup strain, was added after 24h and the cells were further grown for 24h. After detachment from the crab shell fragments, bacteria were poured into soft-agar and overlaid onto LB plates. Mukerjee's El Tor phage III (a gift of Dr. M.S. Islam) was dropped onto the surface of the bacteria containing soft-agar. The plaques formed by killing non-transformed A1552 cells possessed resistant clones which were picked and further selected by non-agglutination with O1-specific antiserum. One to four clones were selected from each independent experiment and analyzed by microarray hybridization (BioPrime. Array CGH Genomic Labeling from Invitrogen). Two microarray replicates were done per clone. Strain Names: AIpO37#1 / AIpO37#4 / AIpO37#6 / AIpO37#8 are clones analyzed from the first experiment; AIIpO37#9 / AIIpO37#13 / AIIpO37#16 are clones analyzed from the second independent experiment; AIIIpO37#9A is a clone analyzed from the third independent experiment; AIVpO37#1A / AIVpO37#3A / AIVpO37#4A / AIVpO37#8A are clones analyzed from the fourth independent experiment. Two MA replicates per clone were done. CGHs of A1552 versus ATCC25872 are provided as control. A genotyping experiment design type classifies an individual or group of individuals on the basis of alleles, haplotypes, SNP's. Keywords: genotyping_design
Project description:Large-genome bacteriophages (jumbo phages) of the Chimalliviriadae family assemble a nucleus-like compartment bounded by a protein shell that protects the replicating phage genome from host-encoded restriction enzymes and CRISPR/Cas nucleases. While the nuclear shell provides broad protection against host nucleases, it necessitates transport of mRNA out of the nucleus-like compartment for translation by host ribosomes, and transport of specific proteins into the nucleus-like compartment to support DNA replication and mRNA transcription. Here we identify a conserved phage nuclear shell-associated protein that we term chimallin C (ChmC), which adopts a nucleic acid-binding fold, binds RNA with high affinity in vitro and binds phage mRNAs in infected cells. ChmC also forms phase-separated condensates with RNA. Targeted knockdown of ChmC using mRNA-targeting Cas13d halts infections at an early stage. Taken together, our data suggest that the conserved ChmC protein acts as a chaperone for phage mRNAs, potentially stabilizing these mRNAs and driving their translocation through the nuclear shell to promote translation and infection progression.