CtrA binds to and regulates the promoters of two genes critical to its temporally controlled proteolysis, divK and clpP, providing a transcriptional feedback loop for the control of cell cycle progression. We propose that a diverse repertoire of condensates can serve as control knobs to tune enzyme sequestration and reactivity in response to the metabolic state of bacterial cells. In addition, minor phospholipids were detected in the swarmer cells that were not detected in stalked cells. Electron microscopy revealed that FzlA organizes FtsZ protofilaments into striking helical bundles. Sorter, A. M., Dahlberg, P. D., Wang, J., Shapiro, L., Moerner, W. E. Environmental Calcium Controls Alternate Physical States of the Caulobacter Surface Layer. Often the outermost cell envelope component, S-layers serve diverse functions including aiding pathogenicity and protecting against predators. von Diezmann, A., Lasker, K., Mann, T. H., Ahrens, D. G., Shapiro, L., Moerner, W. E. Probing Asymmetric Behavior of a Cell Cycle Regupatory Protein in Live Caulobacter using Single-Molecule Imaging, A Red Fluorescent Protein for Cryogenic Single-Molecule Superresolution Imaging. The transcription of gyrB and orf1 occurs from the replication-competent chromosome in stalked and predivisional cells and is silenced in swarmer cells. View details for Web of Science ID A1992JM38600007. We have found that the trans regulation that modulates the amount of the flagellins and the chemotaxis proteins can be separated from the temporal control of fla and che gene expression. View details for DOI 10.1016/S0022-2836(02)01042-2. View details for Web of Science ID 000167833700095, View details for PubMedCentralID PMC31192. Cell cycle synchronization experiments have been used to establish the molecular events governing chromosome replication and segregation, to map a genetic regulatory network controlling cell cycle progression, and to identify the establishment of polar signaling complexes required for asymmetric cell division. The most easily recognized asymmetries involve surface structures, e.g., flagella, pili, and stalks that are preferentially assembled at one pole by many bacteria. We demonstrate here that the time of initiation of flgJ expression is independent of chromosomal location but is dependent upon cis-acting sequences present upstream of the flgJ structural gene. In Caulobacter crescentus the biosynthesis and assembly of this structure is under temporal and spatial control. The diameters of the two upper rings differed, being 32 and 21 nm, respectively. The assembly of a functional flagellum in the bacterium Caulobacter crescentus requires the protein products of approximately 30 genes expressed in a temporally discrete and spatially distinct manner. However, flaO expression appears to be under negative control by two regulatory genes flaS and flaW. In Caulobacter crescentus, the expression of the dnaKJ operon is regulated both temporally during the normal cell cycle and by heat shock. A mutation in the flaD gene results in the assembly of a partial basal body which is missing the outermost P and L rings as well as the external hook and filament (K.M. The effect of cyclic GMP derivatives was shown to be the repression of synthesis of specific structural proteins. In progeny stalked cells, however, accumulated CcrM that has not been degraded before the immediate initiation of DNA replication is sequestered to the cell pole. We sought to identify FtsZ-binding proteins that influence FtsZ function in Caulobacter crescentus. Shapiros lab has identified a pathway conserved from insects to humans, and between steroid hormones and peptide hormones in which mitogenic hormones, such as estrogen, and epidermal growth factor (EGF), elicit extremely rapid anticipatory activation of the stress sensor, the unfolded protein response (UPR). These results are consistent with a model in which unreplicated DNA is pulled into the replication factory and newly replicated DNA is bidirectionally extruded from the complex, perhaps contributing to chromosome segregation. Ryan Rezvani, Amgen Scholar 2014 PhD at UC Irvine A closed-loop control system drives progression of the coupled stalked and swarmer cell cycles of the bacterium Caulobacter crescentus in a near-mechanical step-like fashion. This finite window of opportunity is imposed by coordinating spatially constrained proteolysis of CtrA, an inhibitor of DNA replication initiation, with forward progression of the cell cycle. Interview With Dr. Jonathan Schapiro The first parameter correlates with genome GC content, and the second parameter correlates with context-dependent nucleotide bias. Two heat shock proteins, DnaK and Lon are specifically segregated to the progeny stalked cell. The ctrA gene is preferentially transcribed from a hemimethylated promoter. P(xylX) promoter activity was determined as a function of the composition of the growth medium both in single copy and on a plasmid using different reporter genes. Our current understanding of this system has been limited by the fact that purified protein products are available for only about one-fifth of these genes. Replisome assembly occurs at the chromosomal origin located at the stalked cell pole, coincident with the initiation of DNA replication. Here, we present a mechanism that coordinates assembly and placement of the FtsZ cytokinetic ring with bipolar localization of the newly duplicated chromosomal origins in Caulobacter. These two cell types differ in their program of gene expression, their ability to replicate DNA, and the physical properties of their nucleoids. Vasant Iyer, SURF Scholar 2015 PhD at University of Pennsylvania Our Department is home to about 60 graduate students and 80 postdoctoral fellows who pursue innovative research projects at the leading edge of Developmental Biology. We report the design and application of HaloTag-based target-specific azido DCDHFs, a class of photoactivatable push-pull fluorogens which produce bright fluorescent labels suitable for single-molecule superresolution imaging in live bacterial and fixed mammalian cells. Stanford Both mreB and mreC are essential, and depletion of either protein results in a similar cell shape defect. The mature two-piece tmRNAs are predicted to have a tRNA-like domain and an mRNA-like domain similar to those of standard one-piece tmRNAs, with a break located in the loop containing the tag reading frame. The membrane topology of FliF was determined and a region of the cytoplasmic C-terminal domain was shown to be required for the interaction with a component of the motor switch. View details for DOI 10.1146/annurev.genet.41.110306.130346, View details for Web of Science ID 000252359500018. We annotate the position of PopZ with single-molecule localizations and confirm its position within the ribosome excluded region. Because cell division then yielded a swarmer cell with a different phospholipid profile than its sibling stalked cell, the cell division process may trigger a mechanism which alters the pattern of phospholipid synthesis. SsrA RNA abundance increases in late G(1) phase, peaks during the G(1)-S transition, and declines in early S phase, in keeping with the reported role for SsrA in the timing of DNA replication initiation. Following cell division, only the chromosome in the progeny stalked cell is able to initiate DNA replication, while the chromosome in the progeny swarmer cell does not replicate until later in the cell cycle. press. A partial open reading frame 165 base pairs 3' to the end of dnaK encodes a peptide of 190 amino acids that is 59% identical to DnaJ of E. coli. Compartmentalization of the predivisional cell is a critical event in the establishment of the differential distribution of regulatory factors that specify cell fate. The level of DnaA, a key bacterial DNA replication initiation factor, increases during the Caulobacter swarmer-to-stalked transition just before the G1/S transition. Only the unphosphorylated form of CpdR localizes and activates ClpXP. B.S. Shapiro, Andersen, and Tanter then received an NIH BRAIN Initiative grant to pursue the research. Bowman, G. R., Perez, A. M., Ptacin, J. L., Ighodaro, E., Folta-Stogniew, E., Comolli, L. R., Shapiro, L. Branched signal wiring of an essential bacterial cell-cycle phosphotransfer protein. Of the 26 genes required for flagellum production, at least 4 of them-flaY, E, F, and G-map together in a single cluster. Using DnaA depletion and induction in synchronized cell populations, we have analysed global transcription patterns to identify the differential regulation of normally co-expressed genes. Total phospholipid, DNA, RNA, and protein syntheses were unaffected. A., McAdams, H. H., Shapiro, L. Coordination of chromosome replication and cell cycle progression in Caulobacter, Coordination of DNA replication and cell division in Caulobacter crescentus, Getting organized - how bacterial cells move proteins and DNA, Multiplexed Quantitative Proteomics Using Mass Spectrometry. View details for Web of Science ID 000316243800020, View details for PubMedCentralID PMC3599789. Upon transfer of a mixed population of cells to medium containing lactose as the sole carbon source, these changes were blocked for about 20 hr until beta-galactosidase activity became apparent. B.S. SURF Scholar 2022- Postdoctoral Fellowship, Radiology, Mayo Clinic PopZ therefore functions as a polar hub complex at the cell pole to directly regulate the directionality and destination of transfer of the mitotic segregation machine. Analysis of the cloned C. crescentus dnaA gene has shown that the deduced amino acid sequence can encode a 486-amino-acid protein that is 37% identical to the DnaA protein of Escherichia coli. Bacterial chromosome partitioning and cell division are tightly connected cellular processes. Recent advances in bacterial cell biology have revealed unanticipated structural and functional complexity, reminiscent of eukaryotic cells. The process of establishing asymmetry prior to cell division requires that a number of gene products be targeted to a pole of the predivisional cell and consequently segregated to one of the two progeny. By pulsing synchronized cultures with (14)C-amino acids it has been demonstrated that the synthesis of flagellin occurs approximately 30 to 40 min before cell division. Deletions in the 5' region have also revealed that all cis-acting sites required for temporal control of transcription reside within 50 bases of the P2 start site. We show that DnaA coordinates DNA replication initiation with cell cycle progression by acting as a global transcription factor. Waves and Matter Interaction, cole Normale Suprieure de Cachan View details for Web of Science ID A1976BU75500037. We show that the Caulobacter HdaA homologue is necessary to restrict the initiation of DNA replication to only once per cell cycle and that it dynamically colocalizes with the replisome throughout the cell cycle. Schrader, J. M., Li, G., Childers, W. S., Perez, A. M., Weissman, J. S., Shapiro, L., McAdams, H. H. Cell cycle progression in Caulobacter requires a nucleoid-associated protein with high AT sequence recognition. ctrA is also an essential gene in S. meliloti, and it is expressed similarly to the autoregulated C. crescentus ctrA in that both genes have complex promoter regions which bind phosphorylated CtrA. Nathan, P., Gomes, S. L., Hahnenberger, K., Newton, A., Shapiro, L. FATTY-ACID DEGRADATION IN CAULOBACTER-CRESCENTUS, TRANSCRIPTION INITIATION INVITRO AND INVIVO AT A HIGHLY CONSERVED PROMOTER WITHIN A 16 S-RIBOSOMAL RNA GENE. SsrA, or tmRNA, is a small RNA that interacts with selected translating ribosomes to target the nascent polypeptides for degradation. Although both enzymes protected the same sites on phiCdl DNA from cleavage with HincII, the E. coli enzyme was unable to form stable complexes with some phiCdl restriction fragments that formed stable complexes with the C. crescentus RNA polymerase. In eukaryotes, these functions depend on the orchestrated dynamics of actin filament assembly and disassembly. Using a modified global 5' RACE protocol, we globally mapped transcription start sites (TSSs) at base-pair resolution, measured their transcription levels at multiple times in the cell cycle, and identified their transcription factor binding sites. Researchers develop clever algorithm to improve our Viollier, P. H., Thanbichler, M., McGrath, P. T., West, L., Meewan, M., McAdams, H. H., Shapiro, L. The topoisornerase IV ParC subunit colocalizes with the Caulobacter replisome and is required for polar localization of replication origins, An actin-like gene can determine cell polarity in bacteria, Oscillating global regulators control the genetic circuit driving a bacterial cell cycle. This result establishes the editing site as a bona fide target for aminoacyl-tRNA synthetase inhibitors. In the recent years, considerable advances have been made towards understanding the structure and function of the bacterial chromosome. View details for Web of Science ID A1978FL46900030, View details for Web of Science ID A1977DL60800021. The onset of replication coincides with the stimulation of transcription of several genes involved in the replication process. View details for Web of Science ID 000280561600011, View details for PubMedCentralID PMC3205914.