CSB Seminar: Prof. Zachary Nimchuk, Dept of Biological Sciences and Faculty of Health Sciences, Virginia Polytechnic Institute and State University
CSB Departmental Seminar
Professor Zachary Nimchuk
Department of Biological Sciences
and Faculty of Health Sciences
Virginia Polytechnic Institute and State University
"All Together Now: Receptor Kinase Function in Plant Stem Cell Regulation"
Abstract:
Stem cell populations in plants are controlled by diverse cell-to-cell signaling networks that govern their establishment, size, specific identity and differentiation status. Receptor kinase signaling pathways and their peptide ligands play a prominent role in stem cell regulation in diverse niches. CLAVATA3, a founding member of the CLE family of secreted peptides controls stem cell maintenance via a suite of receptor kinases including members of the CLAVATA1 clade, RPK2, and the co-receptor pair of CLAVATA2/CORYNE. How the distinct receptors quantitatively function in stem cell regulation in response to CLAVATA3 is unclear. Here I will detail recent work in my lab aimed at understanding the functional relationships between the different CLAVATA3 receptors, and some of the new technologies available to dissect genetic redundancy in large gene families.
Host: Profs. Nick Provart & Darrell Desveaux
Refreshments will be served. All are welcome
Video Conferencing at UTM (DV 4001) & UTSc (MW 229)
Ramsay Wright is a Wheelchair Accessible Building
CSB Seminar: Prof. Nadine Peyriéras, Director USR BioEmergences, Gif-sur-Yvette Cedex, France
CSB Departmental Seminar
Dr. Nadine Peyriéras
Director USR BioEmergences
Gif-sur-Yvette Cedex, France
"Multilevel Dynamics in Zebrafish Gastrulation"
Host: Prof. Ashley Bruce
Refreshments will be served. All are welcome
Video Conferencing at UTM (DV 4001) & UTSc (MW 229)
Ramsay Wright is a Wheelchair Accessible Building
Abstract:
We approach the understanding of zebrafish gastrulation, through the quantitative analysis and biomechanical modeling of multiscale in vivo imaging data. The cellular level of organization is taken as resulting from the integration of sub-cellular and supra-cellular processes. Cell dynamics are investigated through 3D+time imaging of developing embryos with fluorescent nuclear and membrane staining. The automated reconstruction of the cell lineage tree, annotated with nucleus and membrane segmentation, provides measurements for cell behavior: displacement, division, shape and contact changes, as well as fate and identity. This quantitative data is sufficient to find statistical models for cell proliferation and cell descriptors evolution in time and space, and characterize the spatial and temporal length scale of cell displacements and tissue deformations. Confronting numerical simulation derived from a multi-agent based biomechanical model with empirical measurements extracted from the reconstructed digital specimens, is the basis for testing hypotheses for processes underlying early embryogenesis. Further correlating cell behavior, tissue biomechanics and biochemical activities by comparing the patterns revealed by cell fate, velocity, strains or gene expression, is a step toward the integration of multi-level dynamics. This overall framework lays the ground for a transdiciplinary approach of living systems’ morphogenesis.
CSB Seminar: Prof. Guy Tanentzapt, Dept of Cellular and Physiological Sciences, University of British Columbia
CSB Departmental Seminar
Professor Guy Tanentzapt
Dept of Cellular and Physiological Sciences
University of British Columbia
"Biomedchanical Regulation of Morphogenesis and Tissue Maintenance by Cell-Matrix Adhesion"
Abstract:
Animal morphogenesis requires force-generating mechanisms to drive the organization of cells into complex three-dimensional structures. At the completion of development dynamic morphogenetic events cease and tissues are stabilized, becoming resistant to the growing strain placed upon them as the organism grows in size. My lab is interested in understanding the role played by cell adhesion to the ExtraCellular Matrix (ECM) during morphogenesis and tissue maintenance. The focus of our research is on integrins, the principal family of adhesion receptors that mediate Cell adhesion to the ECM. Our recent work has illustrated that integrins act as mechanosensors that allow cells to detect and respond to mechanical force. Moreover, we have shown that during morphogenesis integrin provide rheostatic control over force transmission and distribution within developing tissues to promote specific outcomes. Using the tools of genetics, mathematical modelling, biomechanics, and quantitative image analysis of live and fixed embryos we are elucidating the mechanisms by which integrins act as master regulators of morphogenesis and tissue maintenance.
Host: Prof. Ulrich Tepass
Refreshments will be served. All are welcome
Video Conferencing at UTM (DV 4001) & UTSc (MW 229)
Ramsay Wright is a Wheelchair Accessible Building
CSB Seminar: Dr. Sergio Simoes, Cell & Systems Biology, University of Toronto
CSB Departmental Seminar
Dr. Sergio Simoes
Cell & Systems Biology
University of Toronto
"Dynamics and Function of Actomyosin Cytoskeleton and Trafficking of Junctional Regulators during Epithelial to Mesenchyme Transitions"
Host: Prof. Ulrich Tepass
Refreshments will be served. All are welcome
Video Conferencing at UTM (DV 4001) and UTSc (MW 229)
Ramsay Wright is a Wheelchair Accessible Building
Joint CSB & Neuroscience Seminar: Prof. Luis de Lecea, Dept of Psychiatry and Behavioral Sciences, Stanford University
Joint CSB & Neuroscience Seminar
Professor Luis de Lecea
Dept of Psychiatry and Behavioral Sciences
Stanford University
"To Sleep or Not to Sleep: Optogenetics of Arousal"
610 Auditorium, Health Sciences Building
155 College Street
Host:
Prof. John Peever (CSB)
Prof. Richard Horner (Neuroscience)
Abstract:
Our lab studies how brain circuitry controls both sleep and wakefulness in rodent model systems. We are particularly interested in dissecting the role of the hypothalamic circuits in promoting generalized brain arousal. Our work is relevant to understanding common disorders such as narcolepsy and insomnia. Our lab uses innovative approaches such as in vivo optogenetics to examine the exact genetic nature of cells circuits and their roles in shaping behavior.
CSB Seminar: Prof. Vincent Castric, CNRS, Université de Lille
CSB Departmental Seminar
Professor Vincent Castric
CNRS, Université de Lille
"Dominance Hierarchy Rising from the Evolution of a Complex Small RNA Regulatory Network"
Abstract:
The prevention of fertilization through self-pollination (or pollination by a close relative) in the Brassicaceae plant family is determined by the genotype of the plant at the self-incompatibility locus (S locus). The many alleles at this locus exhibit a dominance hierarchy that determines which of the two allelic specificities of a heterozygous genotype is expressed at the phenotypic level. Here, we uncover the evolution of how at least 17 small RNA (sRNA)–producing loci and their multiple target sites collectively control the dominance hierarchy among alleles within the gene controlling the pollen S-locus phenotype in a self-incompatible Arabidopsis species. Selection has created a dynamic repertoire of sRNA-target interactions by jointly acting on sRNA genes and their target sites, which has resulted in a complex system of regulation among alleles.
Host: Daphne Goring
Refreshments will be served. All are welcome!
Video Conferencing at UTM (DV 4001) and UTSC (MW 229)
Ramsay Wright is a Wheelchair Accessible Building
CSB Seminar: Prof. Sally Mackenzie, Ctr for Plant Science Innovation, University of Nebraska-Lincoln
CSB Departmental Seminar
Professor Sally Mackenzie
Centre for Plant Science Innovation
University of Nebraska-Lincoln
"Organelle-mediated Epigenomic Reprogramming in Plants and its Developmental Implications"
Abstract:
The MSH1 gene in plants is a dual targeted protein that participates in stabilizing the mitochondrial and chloroplast genomes. However, multi-functionalization of the protein has resulted in additional properties of the protein within the plastid. Mutation or suppression of MSH1 results in an organelle-mediated process of developmental reprogramming that dramatically alters plant phenotype. This process is accompanied by methylome changes to the nuclear genome that are heritable. More detailed investigation of MSH1 has localized the protein to specialized plastids and to display specialized spatial expression. The epigenetic reprogramming phenomenon that arises with MSH1 suppression presents a unique opportunity for investigating phenotypic plasticity and potential agricultural implications of epigenetic variation.
Host: Prof. Sue Varmuza
Refreshments will be served. All are welcome!
Video Conferencing at UTM (DV 4001) and UTSc (MW 229)
Ramsay Wright is a Wheelchair Accessible Building
Graduate Student Presentations: Timothy Lo (Profs. Guttman & Desveaux Labs) and Francisco Rodrigues (Prof. Harris Lab)
Graduate Student Presentations
Timothy Lo (Profs. Guttman & Desveaux Labs)
"Sibling Rivalry: Functional Diversification of a Pseudomonas syringae Virulence Protein Family"
Containing an armory of virulence proteins, termed type III secreted effectors (T3SEs), the bacterial plant pathogen Pseudomonas syringae infects a wide variety of plant hosts, including tomato and the model plant organism Arabidopsis thaliana. T3SEs are crucial for P. syringae pathogenesis and function primarily to suppress plant immunity. More than 60 families of T3SEs have been identified in P. syringae, including the HopF family of T3SEs. With the increasing number of sequenced P. syringae genomes, the HopF family now contains over forty different family members. Research has predominantly focused on two family members: HopF2 from the tomato/Arabidopsis pathogen P. syringae pathovar tomato DC3000 and HopF1 from the bean pathogen P. syringae pathovar phaseolicola 1449B. Research on the function of these two T3SEs has revealed that HopF2PtoDC3000 can promote virulence in Arabidopsis, while HopF1Pph1449B promotes virulence in beans; yet the function of the remaining HopF family members remains unknown. To investigate the functional differences within this diverse T3SE family, phylogenetic analyses were conducted along with functional characterization on Arabidopsis, beans and soybeans. This analysis revealed that HopF2 from P. syringae pathovar tomato T1 displayed markedly different functional phenotypes compared with the well characterized HopF2PtoDC3000 highlighting the functional diversification within a single T3SE family. Furthermore, the functional difference between these two closely related T3SEs influences the ability of P. syringae to infect Arabidopsis, emphasizing the contribution of T3SE functional diversification to pathogen host range.
Francisco Rodrigues (Prof. Harris Lab)
"Examining an Essential Role for an Arf-GAP in Cell Division"
Regulation of the plasma membrane is essential to ensure proper division of mitotic cells. However, it is still unclear how dividing cells supply membrane to the enclosing furrow. Here, we use the early Drosophila embryo to investigate the role of the ArfGAP Asap during cell division. ArfGAPs are key regulators of membrane trafficking via Arf G protein signaling. We show that the Drosophila Asap is required to promote growth of ingressing metaphase furrows. Potential mechanisms of how this is achieved will be discussed.
Refreshments will be served. All are welcome
Video Conferencing at UTM (DV 4001) and UTSc (MW 229)
Ramsay Wright is a Wheelchair Accessible Building
CSB Seminar: Prof. Sabestien Carreno, CIHR, IRIC-Université de Montréal
CSB Departmental Seminar
Professor Sabestien Carreno
CIHR, IRIC-Université de Montréal
"Cell Morphogenesis during Cell Division"
Abstract:
My laboratory studies molecular networks that regulate cell shape transformations during mitosis. ERM proteins (Ezrin, Radixin, Moesin) anchor actin filaments to the plasma membrane and bind microtubules at the cell cortex. By acting at the interface of the plasma membrane, the actin cytoskeleton and microtubules, ERM proteins are key players in the control of cell morphogenesis. I will present some of our latest discoveries on the role of the interplay between ERM, phosphoinositides and intracellular trafficking for cell shape transformations during cell division.
Host: Prof. Dorothea Godt
Refreshments will be served. All are welcome
Video Conferencing at UTM (DV 4001) & UTSc (MW 229)
Ramsay Wright is a Wheelchair Accessible Building
CSB Seminar: Prof. Sue Varmuza, Cell & Systems Biology, University of Toronto
CSB Departmental Seminar
Prof. Sue Varmuza
Cell & Systems Biology
University of Toronto
"Gateway to the Trophoblast Epigenome; PcG SFMBT2 and Placenta Development"
Abstract:
The placenta is a transient, but critical, extraembryonic organ required for development of mammals. The cell lineage that produces the various types of placenta cells, trophoblast, is particularly sensitive to genomic imprinting, an epigentic process that marks a small subset of genes for silencing on a parent-of-origin basis. Our lab discovered that the rodent PcG gene Sfmbt2 is imprinted in trophoblast; it is expressed robustly from the paternal allele while the maternal allele is silent. Our experiments have revealed that Sfmbt2 is required to maintain the pool of undifferentiated trophoblast progenitor cells, and that mutants lacking this PcG protein have severely reduced placentas, probably reflecting premature differentiation. We are also investigating the mechanism by which the maternal allele is silenced. There is no dependence on DNA methylation; however, a large block of miRNAs present in mouse and rat genes but absent in other mammals correlates with imprinting of Sfmbt2, suggesting that RNAi biochemistry may drive silencing of the maternal allele. Experiments exploring this idea will be discussed.
Host: Prof. Maurice Ringuette
Refreshments will be served. All are welcome
Video Conferencing at UTM (DV 4001) & UTSc (MW 229)
Ramsay Wright is a Wheelchair Accessible Building