Rapid clearance of the master regulator, CtrA, by the ClpXP protease is a critical event that enables the initiation of chromosome replication at specific times in the cell cycle. A Bacterial Toxin Perturbs Intracellular Amino Acid Balance To Induce Persistence. Chemical Engineering (BM), expected 2023 Dibutyryl cyclic adenosine 3',5'-monophosphate (AMP) was shown to stimulate expression of the inducible enzymes and, thus, the initiation of the cell cycle. View details for Web of Science ID A1997XE30000021, View details for PubMedCentralID PMC179208. Two genes encoding the major components of the flagellar filament, the 25K and the 27.5K flagellins, are expressed coincident with flagellar assembly. Toro, E., Hong, S., McAdams, H. H., Shapiro, L. SpoT regulates DnaA stability and initiation of DNA replication in carbon-starved Caulobacter crescentus, A polymeric protein anchors the chromosomal origin/ParB complex at a bacterial cell pole. An adjacent and divergent promoter also has an IHF consensus sequence that binds IHF. Mechanical and Aerospace Engineering, Seoul National University The hybridization method used permits the detection of sequences partially homologous to the elements. SLAC works with two small businesses to make its ACE3P software easier to use in supercomputer simulations for optimizing the shapes of accelerator structures. The Tol-Pal complex is required to maintain the position of the transmembrane TipN polar marker, and indirectly the PleC histidine kinase, at the cell pole, but it is not required for the polar maintenance of other transmembrane and membrane-associated polar proteins tested. Induction of FtsZ curvature by FzlA carries implications for regulating FtsZ function by modulating its superstructure. Our results broadly demonstrate how signaling factors can leverage information from their subcellular niche to drive spatiotemporal control of cell signaling. Phage phiCb5 differs from the E. coli RNA phages in (i) host specificity, (ii) salt sensitivity, and (iii) the presence of histidine, but not methionine, in the coat protein. A novel promoter motif for Caulobacter cell cycle-controlled DNA replication genes, The control of temporal and spatial organization during the Caulobacter cell cycle, Bacterial pathogenesis: Delivering the payload, Caulobacter Lon protease has a critical role in cell-cycle control of DNA methylation. WebBrett Shapiro Gravitational waves are predicted to exist by Einstein's Theory of General Relativity. We have shown that the pilA promoter is activated late in the cell cycle and that transcription of the pilin subunit plays an important role in the timing of pilus assembly. All cells must integrate sensory information to coordinate developmental events in space and time. This type of reconstruction is called 4D beam phase space. View details for DOI 10.1128/mBio.03020-20. Superresolution fluorescence microscopy and cryogenic electron tomography (CET) are powerful imaging methods for exploring the subcellular organization of biomolecules. Until recently, a dedicated mitotic apparatus that segregates newly replicated chromosomes into daughter cells was believed to be unique to eukaryotic cells. Postdoctoral Fellowship, U Chicago Inserting four bases in front of the AUG at the 5' end of dnaX mRNA abolishes translation in the correct frame. View details for DOI 10.1111/j.1365-2958.2005.04912.x, View details for Web of Science ID 000233170700012. x@caltech.edu, x=hsp, Erik Schrunk A previously uncharacterized essential protein, MipZ, forms a complex with the partitioning protein ParB near the origin of replication and localizes with the duplicated origin regions to the cell poles. Single-molecule super-resolution fluorescence microscopy conducted in vitrified samples at cryogenic temperatures offers enhanced localization precision due to reduced photobleaching rates, a chemical-free and rapid fixation method, and the potential of correlation with cryogenic electron microscopy. Caulobacter crescentus assembles a single polar flagellum from protein components synthesized at a specific time in the cell cycle. The CtrA master transcriptional regulator is a central control element in Caulobacter cell cycle progression and polar morphogenesis. 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. The chromosome is specifically and dynamically localized over the course of the cell cycle. phiCbK DNA cosediments with Escherichia coli phage T2 DNA and has therefore been assigned an S(20,w) value of 63.5S. x@gmail.com, x=wheesoo1031, Young-Joo Kim, PhD Ph.D. Student, Chemical Engineering Mechanical Engineering, Yonsei University View details for Web of Science ID A1997XV69900030, View details for PubMedCentralID PMC179479. Research Technician article, Thank you to the Howard Hughes Medical Institute for welcoming our group and supporting our vision of biomolecular ultrasound as an emerging technology for basic biology and medicine. View details for Web of Science ID A1989U499000006. Caulobacter crescentus is widely used as a powerful model system for the study of prokaryotic cell biology and development. The basal body consisted of five rings mounted on a rod. The recognition of polar bacterial organization is just emerging. Alternatively, beam scientists can take many measurements of the beam itself and try to reconstruct, sometimes using machine learning, what the beam would look like under different experimental circumstances but those methods require a lot of data and a lot of computational power. 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. Aminoacyl-transfer RNA (tRNA) synthetases, which catalyze the attachment of the correct amino acid to its corresponding tRNA during translation of the genetic code, are proven antimicrobial drug targets. At higher concentrations, calcium ions stabilize monomeric RsaA, which can then transition to the two-dimensional crystalline state. Electronics and Electrical Engineering, Manipal University Research Technician, 2017-18; Amgen Fellow, 2016 Affiliations: Bioengineering, Biochemistry, Neurobiology The characteristics that differentiate one daughter cell from the other result from differential transcription and subcellular positioning of regulatory and structural proteins. As a proof-of-principle demonstration, we investigate the oxidation/reduction state within vitrified Caulobacter crescentus cells. In most cases of cellular asymmetry, bacteria are able to discriminate between the new pole and the old pole and to utilize this information for localization specificity. The ClpXP protease is localized to the Caulobacter cell pole, where it catalyzes the degradation of the CtrA master regulator at specific times in the cell cycle. View details for Web of Science ID A1973O437500058. It consists of 15 lessons that can be completed in a 45 to 50-minute class period. Phospho-signaling proteins and proteases dynamically deployed to specific locations on the cell wall are vital. B.S. The origins of replication of many different bacteria have been shown to reside at specific subcellular locations, but the mechanisms underlying their positioning and segregation are still being elucidated. SsrA, or tmRNA, is a small RNA that interacts with selected translating ribosomes to target the nascent polypeptides for degradation. We can now use particle beam data in a more comprehensive, powerful way to improve our scientific goals at accelerators everywhere, he said. Comparison to other organisms reveals conservation of cell cycle regulatory logic, even if regulatory proteins, themselves, are not conserved. A fourth heat-shock protein was detected with antibody to the C. crescentus RNA polymerase. The significance of this study is the identification of structural elements involved in the oligomerization and DNA binding of a newly discovered NAP in C. crescentus and the demonstration that structural elements are conserved in evolutionarily distant and functionally distinct NAPs. Vasant Iyer, SURF Scholar 2015 PhD at University of Pennsylvania At the non-permissive temperature, one such mutant, LS439, could not initiate new rounds of DNA replication and arrested primarily as cells with two completed chromosomes Extended incubation at the restrictive temperature resulted in filament formation. View details for Web of Science ID A1994MQ86600007. View details for Web of Science ID 000246369400027. View details for DOI 10.1021/jacs.6b05943, View details for PubMedCentralID PMC4996739. On the basis of these interactions, a trans-acting hierarchy of flagellar and chemotaxis gene expression is proposed. Understanding of the cell cycle control logic in Caulobacter has progressed to the point where we now have an integrated view of the operation of an entire bacterial cell cycle system functioning as a state machine. Beyond direct protein coding, genomes encode regulatory information required to orchestrate the proper timing and levels of gene expression and protein synthesis, and contain binding sites and regulatory sequences to co-ordinate the activities of proteins involved in chromosome repair and maintenance. B.S. Professor, Department of Chemistry
The cellular location of a derivative of the RK2 plasmid is distinct from that of the alpha proteobacterium genomic replicon origins but is conserved across bacteria. The host RNA polymerase appears to be involved in the early transcription program of the Caulobacter crescentus bacteriophage phiCdl. The coincident block in both the initiation of DNA replication and membrane assembly, exhibited by starved cultures of this mutant, suggests that the fatB503 gene product may be involved in the coordination of these events. In addition, we identified two previously unidentified N(6)-methyladenine motifs and showed that they maintained a constant methylation state throughout the cell cycle. Shapiro, L., Grossman, L. I., Marmur, J., KLEISCHM, A. K. SYMPOSIUM ON REPLICATION OF VIRAL NUCLEIC ACIDS .2. The flaS transcript initiation site was identified, and an apparently unique promoter sequence was found to be highly conserved among the genes at the same level of the hierarchy. The promoters for the flgF operon and the flgH gene use sigma 54 to initiate transcription. In wild-type cells, components of the Tol-Pal complex localize to the division plane in early predivisional cells and remain predominantly at the new pole of swarmer and stalked progeny upon completion of division. liqunyu2@illinois.edu
2017 Indian Institute of Technology, University of Wisconsin-Madison
Here, we report that CckA, the histidine kinase upstream of CtrA, employs a tandem-PAS domain sensor to integrate two distinct spatiotemporal signals. Key insights into bacterial regulatory programs that orchestrate cell cycle progression have come from studies of Caulobacter crescentus, a bacterium that divides asymmetrically. Monitoring of a fluorescent marker for CtrA showed that the differential degradation of CtrA in the nascent stalk cell compartment occurs only after the cytoplasm is compartmentalized. B.S. The two enzymes differ, however, in the recognition of specific cleavage sites and yield different digestion products when either coliphage T7 or C. crescentus phage phi Cdl early mRNA is used as substrate. In many cases, a large number of upstream signals are funneled to a master regulator of cellular behavior, but it remains unclear how individual proteins can rapidly integrate a complex array of signals within the appropriate spatial niche within the cell. These genes function in trans to regulate the expression of the flagellin genes and the chemotaxis genes. 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. Mutations in these three genes resulted in the inability of the flagellum to reverse the direction of rotation. The hipA2-encoded kinase functions as a toxin in Caulobacter, inducing bacterial persistence by disturbing the intracellular tryptophan-glutamine balance. B.S. Shapiro (2018). Aero. The nucleoid was formerly perceived to be an amorphous entity divided into ill-defined domains of supercoiling that are randomly deposited in the cell. Bacteria deploy proteins and protein complexes to particular locations and do so in a dynamic manner in lockstep with the organized deployment of their chromosome. Cori has features that both affiliate and distinguish it from the Escherichia coli chromosome replication origin. Contreras, I., WEISSBORN, A., Amemiya, K., MANSOUR, J., Henry, S., Shapiro, L., Bender, R. INVOLVEMENT OF THE HOST RNA-POLYMERASE IN THE EARLY TRANSCRIPTION PROGRAM OF CAULOBACTER-CRESCENTUS BACTERIOPHAGE PHI-CDL DNA, DIFFERENTIAL MEMBRANE PHOSPHOLIPID-SYNTHESIS DURING THE CELL-CYCLE OF CAULOBACTER-CRESCENTUS. Many predivisional cells have bright polar SMC foci, which are lost upon cell division. 38:164-198, 1974; Wolfner et al., J. Mol. The partial IS sequences may represent silent evolutionary remnants or they could modulate the expression of genes carrying these sequences. Abedi MH#, Yao M#, Mittelstein DR, Bar-Zion A, Swift MB, Lee-Gosselin A, Barturen-Larrea P, Buss MT, Shapiro MG*. Bryan, R., Purucker, M., Gomes, S. L., Alexander, W., Shapiro, L. GENETIC-ANALYSIS AND CHARACTERIZATION OF A CAULOBACTER-CRESCENTUS MUTANT DEFECTIVE IN MEMBRANE BIOGENESIS. View details for DOI 10.1128/JB.185.16.4997-5002.2003, View details for Web of Science ID 000184692800037, View details for PubMedCentralID PMC166474. Yoo S, Mittelstein DR, Hurt RC, Lacroix JJ, Shapiro MG*. Here, we explore the role of the coexpressed MreC protein in Caulobacter and show that it forms a periplasmic spiral that is out of phase with the cytoplasmic MreB spiral. She attended the NIH-funded Medical Scientist Training Program at Duke University, where she earned her Ph.D. with Dr. Anthony Means studying calmodulin-dependent kinases in male germ cell development. Our doctoral program in the field of economic analysis and policy prepares students for research careers in economics. Galactose is initially converted to galactonate by galactose dehydrogenase and then 2-keto-3-deoxy-6-phosphogalactonate aldolase catalyzes the hydrolysis of 2-keto-3-deoxy-6-phosphogalactonic acid to yield triose phosphate and pyruvate. A., Deacon, A. M., Shapiro, L. Cell fate regulation governed by a repurposed bacterial histidine kinase.