Yaxin Xu, Research Assistant 2016-2019 PhD at UCSB August, J. T., EOYANG, L., FRANZE DE FERNANDEZ, M. T., Hasegawa, S., Kuo, C. H., RENSING, U., Shapiro, L. Resolution of two factors required in the Q-beta-RNA polymerase reaction. View details for Web of Science ID A1991EW29800007. Dahlberg, P. D., Sartor, A. M., Wang, J., Saurabh, S., Shapiro, L., Moerner, W. E. Integration of cell cycle signals by multi-PAS domain kinases. At room temperature, the ratio of roGFP2 emission brightness when excited at 425 nm or 488 nm is known to report on the local redox potential. Citation: Roussel, Edelen et al., Physical Review Letters, 5 April 2023 (https://doi.org/10.1103/PhysRevLett.130.145001). B.S. Aadyot Bhatnagar, SURF Scholar 2016 Salesforce View details for Web of Science ID 000083885400003. The ensuing accumulation of CtrA results in the activation of the P2 promoter and the repression of the P1 promoter late in the cell cycle. Cryogenic correlative light and electron microscopy (cryo-CLEM) seeks to leverage orthogonal information present in two powerful imaging modalities. The precise and robust regulation of gene expression is a cornerstone for complex biological life. Signals from probes binding the same message are correlated. Therefore, we were able to recover a pH-conditional mutant in a cytoplasmic gene product. We report here that ctrA expression is under the control of two promoters: a promoter (P1) that is active only in the early predivisional cell and a stronger promoter (P2) that is active in the late predivisional cell. Homologs of CcrM are widespread in the alpha subdivision of the Proteobacteria, suggesting that methylation at GANTC sites may have important functions in other members of this diverse group as well. View details for Web of Science ID 000170907900034. The gene is located 2 kb from the origin of replication. View details for DOI 10.1016/j.jsb.2022.107881. This detailed beam information will help scientists perform their experiments more reliably a need that is becoming increasingly important as accelerator facilities operate at higher and higher energies and generate more complex beam profiles. Welcome ARGs 2.0! Collaboration: It is transcribed from three promoters; one is heat inducible, and the other two are induced at the transition from swarmer to stalked cell, coincident with the initiation of DNA replication. Membrane phospholipid synthesis was inhibited in Caulobacter crescentus by growth of a glycerol auxotroph in the absence of glycerol or by treatment with the antibiotic cerulenin. This is an example of controlled proteolysis of a cytoplasmic protein that is associated with its active recruitment to a specific subcellular address. B.S. University of California, San Francisco, Gabrielle Ho Presidents Council Faculty Scholar Award, UT Health SA (UTHSCSA), 2013-2015. Accordingly, we identified, cloned, and sequenced a chromosomal locus, xylX, from Caulobacter crescentus which is required for growth on xylose as the sole carbon source and showed that transcription from a single site is dependent on the presence of xylose in the growth medium. Mechanical Engineering, Yonsei University We report a hybrid simulation of the coupled cell-cycle control system, including asymmetric cell division and responses to external starvation signals, that replicates mRNA and protein concentration patterns and is consistent with observed mutant phenotypes. NSF Fellow Although these strains exhibit different morphologies and DNA content, the replication of both strains in macrophages is attenuated. Dye, N. A., Pincus, Z., Fisher, I. C., Shapiro, L., Theriot, J. View details for DOI 10.1002/cphc.201100686, View details for Web of Science ID 000301537300020. Caulobacter crescentus carries a flagellum and is motile only during a limited time in its cell cycle. Childers, W. S., Xu, Q., Mann, T. H., Mathews, I. I., Blair, J. 169:1493-1498, 1987). View details for Web of Science ID A1982PG49500029, View details for Web of Science ID A1981MJ92600005. A single flagellum is assembled at the swarmer pole of the predivisional cell and is released later in the cell cycle. A conditional genetic screen for CckA mislocalization mutants, using automated fluorescence microscopy and an image processing platform, revealed that the essential DivL protein kinase promotes CckA localization, autophosphorylation, and activity at the new cell pole. The synthesis of both natural fla gene products and the accessed NPTase II was assayed in these strains using antisera to purified components of the flagellum and to purified NPTase II. View details for Web of Science ID 000361534800042, View details for PubMedCentralID PMC4541484. Gloria Ha, SURF Scholar 2015 PhD at Harvard Phosphorylation signals, DNA methylation, differential chromosome structures, protein targeting, and selective protein degradation are also involved in establishing and maintaining cellular asymmetry. Sophie Dalfonzo This conserved pattern is propagated during the course of DNA segregation. Regulated timing of these cellular modules stems from global genetic circuits that allow precise temporal activation with respect to cell cycle progression and cell differentiation. & Gerardot, C. J. In addition to the motility phenotype, mutations in this locus also cause abnormal cell division. For any questions or concerns, please feel free to reach out by emailing Scott Gerbert at In addition, we demonstrate that borinic esters inhibit menaquinone methyltransferase in gram positive bacteria using a new biochemical assay for MenH from Bacillus subtilis. This positional bias of MCPs within predivisional cells could reflect either a large compartment or membrane domain within the incipient swarmer cell, or a gradient of MCPs, with the highest concentration in the vicinity of the flagellum. 2001-2006. The DivL pseudo-histidine kinase, positioned at one cell pole, regulates cell-fate by controlling the activation of the global transcription factor CtrA via an interaction with the response regulator (RR) DivK. AN UNUSUAL PROMOTER CONTROLS CELL-CYCLE REGULATION AND DEPENDENCE ON DNA-REPLICATION OF THE CAULOBACTER-FLILM EARLY FLAGELLAR OPERON, PROTEIN LOCALIZATION AND ASYMMETRY IN THE BACTERIAL-CELL, FLOW-CYTOMETRY OF CAULOBACTER-CRESCENTUS - IDENTIFICATION AND CHARACTERIZATION OF A CELL-CYCLE MUTANT. SciP is expressed late in the cell cycle and accumulates preferentially in the daughter swarmer cell. Bar-Zion A, Nourmahnad A, Mittelstein DR, Shivaei S, Yoo S, Buss MT, Hurt RC, Malounda D, Abedi MH, Lee-Gosselin A, Swift MB, Maresca D, Shapiro MG*. While PodJS has a specific temporal and spatial address, MmpA is present throughout the cell cycle; furthermore, periplasmic fusion to mRFP1 suggested that MmpA is uniformly distributed around the cell. View details for Web of Science ID 000341639600002. We demonstrate here that each of these genes is also required for the expression of chemotaxis methylation genes known to map elsewhere on the chromosome. When sufficient details accumulate, as for Caulobacter cell cycle regulation, the system design has been found to be eminently rational and indeed consistent with good design practices for human-designed asynchronous control systems. Genetic networks with tens to hundreds of genes are difficult to analyze with currently available techniques. C. crescentus is, to our knowledge, the first free-living alpha-class proteobacterium to be sequenced and will serve as a foundation for exploring the biology of this group of bacteria, which includes the obligate endosymbiont and human pathogen Rickettsia prowazekii, the plant pathogen Agrobacterium tumefaciens, and the bovine and human pathogen Brucella abortus. Identification of additional regulatory genes activated by CtrA will serve to directly connect new regulatory modules to the network controlling cell cycle progression. Chromosome replication is restricted to the stalked cell by a unique chromosome origin of replication that may be regulated by a novel cell-specific transcriptional control system. PopZ recruitment of ParA stimulates ParA to assemble on the nucleoid near the PopZ-proximal cell pole. Awards: NIH Pioneer, Mark, IEEE Hertz, Vilcek, Saville, Tsien, Dreyfus, Van Ness, Packard, Sontag, Pew, DARPA YFA, BWF-CASI, Miller, Hertz, Soros, LSRF, TR35 The cellular levels of CtrA and GcrA are temporally and spatially out-of-phase during the cell cycle, with CtrA repressing gcrA transcription and GcrA activating ctrA transcription. Research Technician The chromosome is specifically and dynamically localized over the course of the cell cycle. As a result of the altered genetic structure, these tmRNAs are composed of two distinct RNA molecules. The eukaryotic mitotic machinery uses the cytoskeleton to move specific chromosomal regions. Postdoctoral Scholar, 2016-19 The tad (tight adherence) locus encodes a protein translocation system that produces a novel variant of type IV pili. Macnab, J. Bacteriol. [email protected] Inclusion in this family of proteins suggests that FliQ and FliR may participate in an export pathway required for flagellum assembly. Mutations in the C-terminal domain also blocked discrete steps in the assembly of higher-order structures. Replisome assembly occurs at the chromosomal origin located at the stalked cell pole, coincident with the initiation of DNA replication. Transcription from a strong promoter within the origin occurs uniquely from the replication-competent chromosome at the stalked pole of the predivisional cell. Meisenzahl, A. C., Shapiro, L., Jenal, U. In contrast to the protein components of the hook and filament, the protein encoded by the flaD gene contains a hydrophobic leader peptide. Caltech Ph.D. Student, Bioengineering and. A., McGrath, P. T., Reisenauer, A., McAdams, H. H., Shapiro, L. Single molecules of the bacterial actin MreB undergo directed treadmilling motion in Caulobacter crescentus. This results in photonic crystals with well-resolved and narrow optical reflectivity features, whose wavelengths are determined by the etching parameters. We constructed a reporter that utilizes the urcA promoter to produce a UV-excitable green fluorescent protein in the presence of the uranyl cation, a soluble form of uranium. In eukaryotes, these functions depend on the orchestrated dynamics of actin filament assembly and disassembly. Collaboration: In-vivo Drug Evaluation, University of Colorado and Health Sciences Center GapR interacts with adenine and thymine (AT)-rich chromosomal loci, associates with the promoter regions of cell cycle-regulated genes, and shares hundreds of recognition sites in common with known master regulators of cell cycle-dependent gene expression. A Bacterial Toxin Perturbs Intracellular Amino Acid Balance To Induce Persistence. Because typical organic fluorophores can emit significantly more photons than average fluorescent proteins, organic fluorophores have a potential advantage in super-resolution imaging schemes, but targeting to specific cellular proteins must be provided. Caulobacter crescentus initiates a single round of DNA replication during each cell cycle. The two-component signaling protein CtrA activates or represses the expression of one-quarter of the cell-cycle-regulated genes in Caulobacter crescentus, integrating DNA replication, morphogenesis, and cell division. Understanding the control logic in the bacterium Caulobacter crescentus has progressed to the point where we now have an integrated systems view of the operation of its entire cell cycle functioning as a state machine. The transposons were altered so that upon insertion into the chromosome, transcription fusions are formed in which the promoter regions of fla genes drive the expression of the downstream promoter-less drug resistance genes. Homologs of GapR, which are ubiquitous among the -proteobacteria and are encoded on multiple bacteriophage genomes, also accumulate in the predivisional cell swarmer compartment when expressed in Caulobacter The Escherichia coli nucleoid-associated protein H-NS, like GapR, selectively associates with AT-rich DNA, yet it does not localize preferentially to the swarmer compartment when expressed exogenously in Caulobacter, suggesting that recognition of AT-rich DNA is not sufficient for the asymmetric accumulation of GapR. B.S. Professor of Biochemistry & Basic Medical Sciences, College of Medicine WebDr. Hear Jeffs story. 38:164-198, 1974; Wolfner et al., J. Mol. Ph.D. Student, Medical Engineering, Defended 2022 Only the unphosphorylated form of CpdR localizes and activates ClpXP. View details for DOI 10.1111/j.1365-2958.2010.07222.x, View details for Web of Science ID 000279168200007, View details for PubMedCentralID PMC2915588. Director, Center for Molecular and Cellular Medicine Purified SMC-E1076Q was deficient in ATP hydrolysis and exhibited abnormally stable binding to DNA. With the annotated genome sequence, a full description of the genetic network that controls bacterial differentiation, cell growth, and cell cycle progression is within reach. We describe the identification of 27 novel Caulobacter crescentus sRNAs by analysis of RNA expression levels assayed using a tiled Caulobacter microarray and a protocol optimized for detection of sRNAs. Moreover, active transport processes ensure the efficient segregation of sister chromosomes and the faithful restoration of nucleoid organization while DNA replication and condensation are in progress. At the swarmer-to-stalked cell transition and in the stalked compartment of the predivisional cell, CtrA is localized to the cell pole just before its degradation. View details for DOI 10.1073/pnas.1220824110, View details for Web of Science ID 000314558100027, View details for PubMedCentralID PMC3562846. View details for Web of Science ID 000073041000027, View details for PubMedCentralID PMC107146. Faithful cell cycle progression in the dimorphic bacterium Caulobacter crescentus requires spatiotemporal regulation of gene expression and cell pole differentiation. Learn more about the places where science happens at SLAC: our major facilities, institutes and centers. Vivek Bharadwaj, Ph11 Scholar 2017 PhD at UC Berkeley, Making engineered cells dance to ultrasound, Researchers Make it Possible for Ultrasound to Reveal Gene Expression in the Body, Vilcek Foundation Prize Awarded to Mikhail Shapiro, CCE Postdoc Receives NIH Pathway to Independence Award, Mikhail Shapiro Wins Roger Tsien Award for Excellence in Chemical Biology, Program Brings Area High School Students, Teachers into Caltech Labs, Switching Brain Circuits On and Off Without Surgery, Mikhail Shapiro Selected as Camille Dreyfus Teacher-Scholar, Taking MRI Technology down to Micrometer Scales, Scientists Design Bacteria to Reflect Sonar Signals for Ultrasound Imaging, Biologists Give Bacteria Thermostat Controls, Designing Ultrasound Tools with Lego-Like Proteins, Newly Named Pew Scholar to Image Gut Bacteria with Sound Waves, Partnership with Heritage Medical Research Institute Will Augment Translational Medicine Research, Abedi Receives Fellowship for New Americans, Caltech Researchers Receive NIH BRAIN Funding, New Method Could Improve Ultrasound Imaging, [email protected]; x=mikhail
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