An impressively diverse array of mechanisms underlies bacterial polarity, including oscillatory systems, phospho-signaling pathways, the sensing of membrane curvature, and the integration of cell cycle regulators with polar maturation. Director, High-throughput Screening Facility
Here, utilizing genetic, biochemical, and biophysical studies of GapR in light of a recently published DNA-bound crystal structure of GapR, we identified the structural elements involved in oligomerization and DNA binding. View details for Web of Science ID A1978FL46900030. Professor of Psychiatry and of Neurobiology, Division of Molecular Psychiatry, Yale University School of Medicine, 34 Park Street - CMHC, New Haven, CT 06508, (203) 974-7684. View details for DOI 10.1016/j.bpj.2011.02.022, View details for Web of Science ID 000289494200001, View details for PubMedCentralID PMC3072666. Included are those involved in chemotaxis, outer membrane channel function, degradation of aromatic ring compounds, and the breakdown of plant-derived carbon sources, in addition to many extracytoplasmic function sigma factors, providing the organism with the ability to respond to a wide range of environmental fluctuations. 725 Albany St 1st Floor Boston . View details for Web of Science ID A1993LX92900005, View details for Web of Science ID A1993LF06100004, View details for Web of Science ID A1993LF06100002, View details for Web of Science ID A1993KX96501075, View details for Web of Science ID A1993KX96501060. Dutka P, Metskas LA, Hurt RA, Salahshoor H, Wang TY, Malounda D, Lu GJ, Chou TS, Shapiro MG*, Jensen GJ*. The latter two motifs are implicated in essential C. crescentus replication functions, because they are contained within specific deletions that abolish replication. Analysis of the fliX-flgI intergenic region revealed an arrangement of cis-acting elements similar to that of another set of Caulobacter class II and class III flagellar genes, fliL-flgF, that is also divergently transcribed. The conserved nucleotides in the promoter region are clustered in the -10, -20 to -30, and -35 regions. We have identified a novel, conserved protein, RcdA, that forms a complex with CtrA and ClpX in the cell. Mollie Friedlander Qian in Seung Kims lab successfully defended her thesis titled Discovering new functions of the diabetes gene HNF1A in human pancreatic islets on February 8, 2022. These results indicate that the rapidly reassociating fraction derives from inverted repeat sequences within the chromosome and not from cross-links or plasmids. Cell division in Gram-negative organisms requires coordinated invagination of the multilayered cell envelope such that each daughter receives an intact inner membrane, peptidoglycan (PG) layer and outer membrane (OM). LOEWY, Z. G., Bryan, R. A., REUTER, S. H., Shapiro, L. ASYMMETRIC SEGREGATION OF HEAT-SHOCK PROTEINS UPON CELL-DIVISION IN CAULOBACTER-CRESCENTUS, CASCADE REGULATION OF CAULOBACTER FLAGELLAR AND CHEMOTAXIS GENES, IDENTIFICATION OF A GENE-CLUSTER INVOLVED IN FLAGELLAR BASAL BODY BIOGENESIS IN CAULOBACTER-CRESCENTUS, SEPARATION OF TEMPORAL CONTROL AND TRANS-ACTING MODULATION OF FLAGELLIN AND CHEMOTAXIS GENES IN CAULOBACTER. However, both cell division and stalk formation, which is analogous to a polar division event, require SecA function. The resulting plasmid was used as a probe to isolate the flaE region from a wild-type gene bank and to determine the chromosomal location of several deletion and insertion mutations within the flaY/E/F/G cluster. The hclA and the fatA genes mapped close together, possibly implying that comutation had occurred in AE6002. Congratulations to Avinoam and colleagues on showing that cells can be engineered to migrate into tumors and damage them from the inside upon receiving a focused ultrasound stimulus. Gober, J. W., CHAMPER, R., Reuter, S., Shapiro, L. IDENTIFICATION OF CIS AND TRANS-ELEMENTS INVOLVED IN THE TIMED CONTROL OF A CAULOBACTER FLAGELLAR GENE. Two distinct protein complexes, the flagellum and the pilus biogenesis machinery, are asymmetrically assembled at one pole of the Caulobacter predivisional cell. The flaD mutant, however, was found to contain a partially assembled basal body consisting of the rod and three hook-distal rings. View details for Web of Science ID A1984TP18100004. She received her medical degree from Stanford University School of Medicine and has been in practice between 6-10 years. Here we demonstrate that the Caulobacter PopZ scaffold creates an organizing center at the cell pole that actively regulates polar centromere transport by the ParA partition system. Phosphorylated CtrA (CtrA approximately P) bound to the CtrA recognition sequence in both promoters but had a 10- to 20-fold greater affinity for PfliQ. Kim, S., Gitai, Z., Kinkhabwala, A., Shapiro, L., Moerner, W. E. A phospho-signaling pathway controls the localization and activity of a protease complex critical for bacterial cell cycle progression. View details for DOI 10.1128/JB.185.10.3068-3075.2003, View details for Web of Science ID 000182686900012, View details for PubMedCentralID PMC154060. Differential translation of operon-encoded genes facilitates precise cell cycle-timing for the dynamic assembly of multiprotein complexes, such as the flagellum and the stalk and the correct positioning of regulatory proteins to specific cell poles. Moreover, we show that GapR is maintained as a tetramer upon its dissociation from DNA and that tetrameric GapR is capable of binding DNA molecules in vitro Analysis of protein chimeras revealed that two helices of GapR are functionally conserved in H-NS, demonstrating that two evolutionarily distant NAPs with distinct mechanisms of action utilize conserved structural elements to oligomerize and bind DNA.IMPORTANCE Bacteria organize their genetic material in a structure called the nucleoid, which needs to be compact to fit inside the cell and, at the same time, dynamic to allow high rates of replication and transcription. The cell-cycle control has a cyclical genetic circuit composed of four regulatory proteins with tight coupling to processive chromosome replication and cell division subsystems. The aggregation pattern changes as a function of the cell cycle both during and upon completion of chromosome replication. These mutants and the wild-type strain were used to determine the pathway of galactose catabolism in this organism. Double-stranded side branches between 100 and 600 nucleotide pairs in length were visible in electron micrographs of rapidly reassociating deoxyribonucleic acid isolated by hydroxyapatite chromatography. The principal analysis method involved identification of sets of adjacent probes with unusually high correlation between the individual intergenic probes within the set, suggesting presence of a sRNA. Strategies to encode or label small particles or beads for use in high-throughput screening and bioassay applications focus on either spatially differentiated, on-chip arrays or random distributions of encoded beads. As developmental biologists, we aspire to understand how pluripotent cells become diversified into lineages ranging from brain to blood to bone. Biteen, J. S., Shapiro, L., Moerner, W. E. The role of a bacterial SMC in chromosome segregation. From Will Chueh: "Creativity is one of the most important ingredients to doing impactful research. With time-lapse imaging, polymerized MreB [filamentous MreB (fMreB)] and unpolymerized MreB [globular MreB (gMreB)] monomers could be distinguished: gMreB showed fast motion that was characteristic of Brownian diffusion, whereas the labeled molecules in fMreB displayed slow, directed motion. Drug Discovery, Small Molecule Synthesis, University of Illinois
The outcome of these experiences, together with the extraordinary scientists I came to know along the way, was and is an abiding passion to fully understand a simple cell in all its complexity and beauty. A specialized protein secretion pathway is used by some Gram-negative bacterial pathogens for delivery of virulence factors directly into mammalian host cells. As developmental biologists, we aspire to understand how pluripotent cells become diversified into lineages ranging from brain to blood to bone. 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. Biophysical analysis of purified wild type and assembly defective mutant proteins indicates that PopZ self-associates into an elongated trimer, which readily forms a dimer of trimers through lateral contact. 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. Bacteria regulate chromosomal replication from one specific origin. Although transcription from the smc promoter is induced during early S phase, a cell cycle transcription pattern previously observed with multiple DNA replication and repair genes, the SMC protein is present throughout the entire cell cycle. This event will be held at the Stanford Memorial Auditorium on campus. that influence the observed structures remains absent. The essential transcriptional circuitry for growth on rich media includes 10 transcription factors, 2 RNA polymerase sigma factors and 1 anti-sigma factor. This result allowed us to deduce that the mechanism of fatty acid desaturation in C. crescentus is anaerobic, as it is in E. coli. I earned my undergraduate degree from the University of Toronto and have previously worked as a predoctoral research fellow at the Gentzkow-Shapiro Lab at Stanford University. Cryo-electron microscopy images of the Caulobacter cell envelope exhibited outer membrane disruption, and cells failed to complete cell division in TolA, TolB, or Pal mutant strains. Dr. Shapiro's laboratory question in developmental biology involves the mechanisms used to generate the three-dimensional organization of a cell from a one-dimensional genetic code. View details for Web of Science ID A1979HV87000039. View details for Web of Science ID A1977DU20100033, View details for Web of Science ID A1976CH91600017. The PleA protein contains a region that is similar to a peptidoglycan-hydrolytic active site, and a point mutation at this site in PleA results in the loss of flagellum and pili biogenesis. View details for DOI 10.1073/pnas.0402567101, View details for Web of Science ID 000222278600017, View details for PubMedCentralID PMC438962. Located on the first floor of the Shapiro Undergraduate Library, the Lab bosts ownership of four 3D printers, a 3D printer pen, a silhouette vinyl cutter, an 18th century letter press, a heavy duty singer sewing machine, two soldering stations, and a VR station with an Oculus and Vive. We have identified a single amino acid substitution in the Caulobacter structural maintenance of chromosomes (SMC) protein that disrupts chromosome segregation and cell division. Next to this is the third region, which is approximately 60 nm in length. Caulobacter crescentus initiates a single round of DNA replication during each cell cycle. This gene was cloned, and it was found that its transcription is initiated early in the cell cycle. Thus, we propose that the Caulobacter chromosomal origins have specific cellular addresses and that the SMC protein plays important roles in maintaining chromosome structure and in partitioning. View details for Web of Science ID A1990CW01800056. Stanford Center for Professional Development. Polyakova, M., & Shapiro, J. He earned B.A. 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. The occurrence of the recognition sequence for an essential DNA methylating enzyme that is required for cell cycle regulation is severely limited and shows a bias to intergenic regions. Nucleoid-associated proteins (NAPs) play a pivotal role in this process, so their detailed characterization is crucial for our understanding of DNA organization into bacterial cells. Bayas, C. A., Schrader, J. M., Lee, M. K., Shapiro, L., Moerner, W. E. CauloBrowser: A systems biology resource for Caulobacter crescentus. We offer consultative services to pathologists around the world who seek assistance with challenging cases. The sequences of the N and C termini of the Salmonella typhimurium flagellar axial proteins, rod, hook and HAP-1, known to be highly conserved, share a high degree of sequence identity with the FlgF and FlgG rod proteins of the distantly related, C. crescentus. We demonstrate that successive cleavage events involving regulated intramembrane proteolysis (Rip) occur as a function of time during the Caulobacter cell cycle. On the other hand, several differences were found between the C. crescentus and E. coli RNA polymerases with respect to their interaction with Caulobacter phage phiCdl DNA. View details for DOI 10.1128/mBio.00448-20. Under these conditions, the cell enters a quiescent state referred to as dormancy or persistence. The transduction of the chemotaxis signal is initiated by a chemoreceptor-CheW-CheA ternary complex at the inner membrane. lwang213@ilinois.edu
Francois Jacob (1920-2013). We focus on mRNA processing, RNA modifications and their roles in development and disease. The cell cycle-dependent proteolysis of FliF and the targeting of FliF to the swarmer pole together contribute to the asymmetric localization of the MS-ring in the predivisional cell. During cell division, multiple processes are highly coordinated to faithfully generate genetically equivalent daughter cells. Using cluster analysis of the resulting set of 12-element vectors for each of these strains, we identified 52 strains with mutations that affected the localization pattern of the three tagged proteins. Importantly, RNase E cluster positions correlated with the subcellular location of chromosomal loci of two highly transcribed rRNA genes, suggesting that RNase E's function in rRNA processing occurs at the site of rRNA synthesis. We have isolated the sigma 54 gene (rpoN) and describe here a novel role for this alternative sigma-factor in cell differentiation: It is required for the biogenesis of both polar structures, and the disruption of the rpoN gene results in aberrant cell division. We compare the regulatory requirements, DNA structures, and biochemical properties of the prototypic Escherichia coli origin with those of evolutionarily distant Bacillus subtilis and Caulobacter crescentus origins. We combine quantitative organism-wide fluorescence imaging ("deep imaging"), functional genomics ("deep sequencing"), and statistical modeling to understand the fundamental rules that control collective cell behaviors to optimize tissue organization, regeneration, adaptation, and evolution. The probe correlation analysis approach reported here is of general use for large-scale sRNA identification for any sequenced microbial genome. A., Fero, M. J., McAdams, H. H., Shapiro, L. Mutations in the nucleotide binding pocket of MreB can alter cell curvature and polar morphology in Caulobacter. The Tn5 insertion mutant SC1130 had no cross-reacting MCP and had reduced levels of activity of the methyltransferase and methylesterase. Caulobacter crescentus provides an excellent model system for the bacterial cell cycle whereby cells can be rapidly synchronized in a G0 state by density centrifugation. However, many of the mechanistic details underlying these functions are unknown. Cells use highly regulated transcriptional networks to control temporally regulated events. Biomolecular enhancers for fUS. Gahlmann, A., Ptacin, J. L., von Diezmann, A. S., Shapiro, L., Moerner, W. E. Quantitative Registration and Distribution Analysis of Multicolor 3D Super-Resolution Images of Proteins Reveals Nanoscale Spatial Organization. Click here to join the member exclusive portion of my show: https://utm.io/ueSEj. By simply increasing the laser power, single molecules of the fluorescent protein fusion HU2-eYFP can be made to blink on and off to achieve super-resolution imaging with a single excitation source. Our results elucidate a bacterial chromosome segregation mechanism that features basic operating principles similar to eukaryotic mitotic machines, including a multivalent protein complex at the centromere that stimulates the dynamic disassembly of polymers to move chromosomes into daughter compartments. MipZ directly interferes with FtsZ polymerization, thereby restricting FtsZ ring formation to midcell, the region of lowest MipZ concentration. Flagellum biogenesis, like cell division, is a morphogenic event that requires the orderly assembly of component proteins and the overlapping gene organization may affect this "ordering" of assembly. 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