Archives Events
CSB Seminar: Mehran Dastmalchi, PhD - Department of Biological Sciences, University of Toronto, Scarborough
CSB Departmental Seminar
Friday, November 21st @ 11:00 am
SPEAKER: Department of Biological Sciences, University of Toronto, Scarborough
TITLE: An odd mutant phenotype yields “parts” for synthetic biology
ABSTRACT: Catharanthus roseus (Madagascar periwinkle) is a medicinal plant that produces an abundance of monoterpenoid indole alkaloids (MIAs), notably the anticancer compounds vinblastine and vincristine. While the canonical pathway is resolved at the enzymatic level, the mechanisms controlling many lateral branches of MIA biosynthesis, as well as their transport, remain largely unknown. Here, we describe an EMS-generated mutant of C. roseus, which accumulates high levels of MIAs, including akuammicine, a promising analgesic compound. In addition to its unique chemical profile, we observed a striking lesion-mimic mutant (LMM) phenotype. My talk will encompass morphological and multi-omic analyses to pinpoint the causal mutation and to describe the cascade of cellular and metabolic events leading to this phenotype. We also draw upon this mutant for new leads on the biosynthesis, regulation, and transport of MIAs, which has led to our recent characterization of CrMATE1, a vacuolar secologanin uptake transporter. Finally, these plant competencies are deployed in a synthetic biology context to improve the titers of medicinal MIAs. From core to specialized metabolism—there are a lot of untapped molecular and biochemical nuances that we seek to explore.
HOST: Stephen Bordeleau
LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432
LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/
Eurico Morais de Sá, PhD - University of Porto -- CSB Seminar
CSB Departmental Seminar
Friday, November 28th @ 11:00 am
SPEAKER: Eurico Morais de Sá, PhD - University of Porto
TITLE: From protein localization patterns to understanding how epithelial cells move and divide
ABSTRACT: Epithelial tissues form cohesive and selective barriers that compartmentalize animal life. While epithelia display a well defined apical-basal architecture, epithelial cells must undergo dramatic cell shape changes to accommodate tissue morphogenesis, migration and cell division. But how do they coordinate cytoskeleton remodelling with intercellular adhesion and polarity to achieve such cell shape plasticity? In this seminar, I will discuss how spatial and temporal regulation of Rho family GTPases governs two key epithelial behaviours — cell division and collective migration. By combining systematic RhoGAP/GEF family-wide GFP localization screens with quantitative imaging analysis in Drosophila and mammalian models, we mapped the distribution of these major families of cytoskeletal regulators and uncovered how precise control of RhoGTPase inhibitors (RhoGAPs) reshapes the mitotic cortex and restricts contractility to fine tune collective movement. These findings advance our understanding of how epithelial tissues preserve their function while dynamically adapting their architecture — a balance essential for animal development and homeostasis.
HOST: Ulli Tepass
LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432
LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/
Ingo Braasch, PhD - Michigan State University -- CSB Seminar
CSB Departmental Seminar
Friday, December 5th @ 11:00 am
SPEAKER: Ingo Braasch, PhD - Michigan State University
TITLE: A Blast From the Past: ‘Living Fossils’ Bridge Gene Regulation Across Long Evolutionary Distances in Vertebrates
ABSTRACT: Identifying cis-regulatory elements (CREs) across distant vertebrate lineages remains a major challenge. Many CREs are undetectable across taxa due to sequence divergence beyond recognition, CRE turnover, and the emergence of lineage-specific regulatory elements. This disconnect is especially pronounced in widely used model systems like rodents and teleost fishes, which exhibit rapid molecular sequence evolution.
Teleosts, including key biomedical models like zebrafish, are often used to study vertebrate genome function and regulation. However, a lineage-specific teleost genome duplication (TGD) drastically reshaped their genome structure and regulatory networks. Their accelerated sequence evolution, likely driven by the TGD, has obscured many ancestral CREs, complicating efforts to trace the evolution of gene regulation across vertebrates.
In contrast, holostean fishes – gars (genera Lepisosteus and Atractosteus) and bowfins (genus Amia) – retain some of the slowest-evolving genomes among vertebrates. These “living fossils” provide a unique window into early bony vertebrate evolution. Their unduplicated genomes, conserved development, and archaic morphologies offer critical insight into deep homologies that have been masked by rapid evolution in the derived teleost and tetrapod lineages.
Leveraging haplotype-resolved genome assemblies from multiple holostean species we use comparative genomics, single-cell transcriptomics, and epigenomic profiling in holosteans to reveal ancestral CREs and recover hidden gene regulatory landscapes across bony vertebrates. The evolutionary stability of holostean genomes enables the identification of conserved vertebrate CREs that would otherwise remain hidden for fast-evolving taxa. Our work underscores the immense value of including slow-evolving lineages across the Vertebrate Tree of Life to reconstruct the deep history of gene regulation and uncover the genome regulatory logic that shapes vertebrate biodiversity.
HOST: Max Shafer
LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432
LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/
Christopher Grefen, PhD - Ruhr-University Bochum -- CSB Seminar
CSB Departmental Seminar
Friday, December 12th @ 11:00 am
SPEAKER: Christopher Grefen, PhD - Ruhr-University Bochum
TITLE: Insertion pathways for membrane proteins in the plant ER
ABSTRACT: Membrane proteins are essential for almost every cellular process, yet the routes they take to reach the endoplasmic reticulum (ER) are surprisingly diverse. While many follow the classical SRP/Sec61 pathway, a growing number rely on alternative, non-canonical routes. These include tail-anchored (TA) proteins and other SRP-lacking proteins with internal transmembrane domains that Sec61 cannot efficiently handle.
In this talk, I will share recent findings from Arabidopsis thaliana that combine mechanistic insights into the Guided-Entry of TA proteins (GET) pathway with the organism-level consequences of pathway loss. I will show how specific lipid species influence GET receptor function and how impaired insertion affects development, tissue differentiation, and stress responses. Finally, I will present unpublished data on the SRP-independent (SND) pathway, revealing how its loss disrupts fertility and why plants rely on this alternative route for proper reproductive development.
HOST: Heather McFarlane
LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432
LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/
Cheng Huang, PhD - Department of Neuroscience, Washington University School of Medicine in St. Louis -- CSB Seminar
CSB Departmental Seminar
Friday, January 9th @ 11:00 am
SPEAKER: Cheng Huang, PhD - Department of Neuroscience, Washington University School of Medicine in St. Louis
TITLE: Decoding dopamine-mediated learning algorithms in the Drosophila brain
ABSTRACT: My research program focuses on understanding the neural circuits underlying memory formation, storage, and retrieval. Using Drosophila as a model system, I am particularly interested in how dopamine signaling modulates neural plasticity and contributes to adaptive behaviors. We employ a multidisciplinary approach, combining advanced imaging techniques, quantitative behavioral assays, and computational modeling to dissect the complex dynamics of dopamine neurons during learning and memory processes. Our latest study reveals how innate valence information regulates memory dynamics and uncovers a mechanism by which short-term memory gates long-term memory formation through dopamine signaling. Specifically, we examined the MB circuit for learning aversive associations. First, we discovered a subset of dopamine neurons that encode negative innate sensory valence information. During learning, these dopamine neurons dynamically integrate this innate valence with learned associations (e.g., the association of the odor with an electric shock). This integrated valence signal then controls long-lasting neural plasticity in downstream neurons. To understand how this learned valence arises, we identified an inhibitory feedback pathway from short-term memory encoding neurons to the dopamine neurons. This pathway underlies the learned valence represented in the dopamine signal, ensuring that only consistent associations generate long-lasting memories. Further, we constructed a computational model using constraints derived from both our large-scale voltage imaging dataset and Drosophila connectome data. We uncovered the computational principle and benefits of dopamine-based valence integration in this learning network. Collectively, our results provide insights into how ecologically relevant information directly governs memory formation and demonstrate the power of integrative research approaches in studying complex brain processes.
HOST: Qian Lin
LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432
LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/
Owen Tamplin, PhD - Department of Cell and Regenerative Biology, University of Wisconsin - Madison -- CSB Seminar
CSB Departmental Seminar
Friday, January 16th @ 11:00 am
SPEAKER: Owen Tamplin, PhD - Department of Cell and Regenerative Biology, University of Wisconsin - Madison
TITLE: The blood stem cell microenvironment: development and function across the lifespan
ABSTRACT: Our lab primarily focuses on understanding the hematopoietic stem cell (HSC) niche microenvironment. HSC transplantation is a curative treatment for many blood diseases and cancers, however, many of these procedures still fail and there is a need to improve success rates. Therefore, a better understanding of the signals and adhesion molecules in the HSC microenvironment that regulate engraftment of HSCs after transplantation, and maintain HSCs in an undifferentiated state, are critical for improving clinical HSC therapies. Our lab uses complementary zebrafish and mouse models for in vivo cell biology and translational studies, respectively. We integrate cutting-edge technologies to gain new perspectives on the HSC microenvironment. We are focused on three main areas of research: 1) Understanding the emergence and migration of HSCs between different sites of hematopoiesis in the embryo; 2) Defining the role of neurotransmitters and metabolites in the HSC niche; 3) Generating new animal models for the study of development and disease.
HOST: Felix Gunawan
LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432
LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/