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Principal Investigator: Denise J. Montell
Organization: UNIVERSITY OF CALIFORNIA SANTA BARBARA
Fiscal Year: 2024
Award: $371,183
Funding agency: National Institute of General Medical Sciences
During normal embryonic development, wound healing and cancer metastasis, cells move collectively,
making and breaking cell-cell contacts as they squeeze between other cells and tissues. Individual cells can
leave an epithelium by undergoing the epithelial to mesenchymal transition. However, the program(s)
enabling cells to escape as a group are less clear. Even less studied are the mechanisms by which groups
of cells establish new connections at their destination. We established an in vivo model, the border cells in
the Drosophila ovary, to study collective cell movements. We deploy the powerful Drosophila genetics toolkit
and organ culture methods we developed to carry out high-resolution live imaging and optogenetics. During
the last funding period, we investigated mechanisms by which border cells separate from the follicular
epithelium in the process of delamination and how they make new connections when they reach the oocyte,
a process we call neolamination. We identified multiple steps of each process and proteins that control them.
In Aim 1, we will address key open questions in the septin field and build on our discoveries that the septin
cytoskeleton is essential for border cell delamination and that the GTPase Rho recruits septins to the cortex.
We propose to use novel in vivo analysis of cell and cluster geometry that we developed to compare and
classify Rho, myosin, and septin phenotypes to clarify their roles and relationships in delamination. We will
identify the GEFs and GAPs that regulate Rho upstream of septins. In Aim 2, we will follow up on our
discovery that the nucleus plays an essential role in collective delamination. As border cells delaminate, they
squeeze into tiny spaces much smaller than even a single nucleus. The nucleus can impede cell movement
through rigid plastic pores, but we found that the nucleus plays a role in promoting border cell delamination.
We propose a new “nuclear wedge” model in which nuclei push substrate cells apart. In Aim 2, we will
decipher the mechanisms that move nuclei within the lead cell to promote its wedge function. We will test the
function of the LIS1/NudE/Dynein pathway, which moves nuclei on microtubules (MTs) during the migration
of neural progenitors in the developing neocortex. We will also study myosin, which transiently accumulates
near sites of nuclear deformation and movement. In Aim 3, we will pursue our discovery that innexin (Inx)
gap junction proteins promote both delamination and neolamination. Inxs function in a MT-dependent but
channel-independent manner. We propose to probe the unexplored relationship between Inxs and MTs. We
recently overcame a major technical hurdle and can now image MT dynamics in vivo, which we will use to
characterize innexin phenotypes. We will decipher the relationship between MT post translational
modifications and dynamics in vivo. We will also test our integrative working model for how nuclear, and
cortical cytoskeletal systems interact to accomplish collective delamination and neolamination in vivo.
Terms: <Actin-Activated ATPase><Actins><Active Follow-up><Address><Automobile Driving><Behavior><Blood><Blood Reticuloendothelial System><Body Tissues><Cancers><Carcinoma Cell><Cell Body><Cell Junctions><Cell Locomotion><Cell Migration><Cell Movement><Cell Nucleus><Cell membrane><Cell model><Cell surface><Cells><Cellular Matrix><Cellular Migration><Cellular Motility><Cellular model><Chemotaxis><Classification><Communicating Junction><Complex><Connexins><Contracting Opportunities><Contracts><Cytoplasm><Cytoplasmic Membrane><Cytoskeletal System><Cytoskeleton><Data><Destinations><Development><Disease><Disorder><Drosophila><Drosophila genus><Dynein><Dynein ATPase><Dynein Adenosine Triphosphatase><Dynein Adenosinetriphosphatase><Elements><Embryo Development><Embryogenesis><Embryonic Development><Environment><Epithelial Cells><Epithelium><Experimental Models><Filament><Funding><Gap Junction Proteins><Gap Junctions><Genes><Genetic><Geometry><Image><Immune><Immunes><In Vitro><In vivo analysis><Individual><Intercellular Junctions><Intermediate Filaments><Lamins><Lead><Location><Low-resistance Junction><Lymph><Malignant Cell><Malignant Epithelial Cell><Malignant Neoplasms><Malignant Pancreatic Neoplasm><Malignant Tumor><Malignant Tumor of the Lung><Malignant neoplasm of lung><Malignant neoplasm of pancreas><Mechanics><Membrane><Metastasis><Metastasis to the Lung><Metastasize><Metastatic Lesion><Metastatic Mass><Metastatic Neoplasm><Metastatic Neoplasm to the Lung><Metastatic Tumor><Metastatic Tumor to the Lung><Methods><Micro-tubule><Microtubules><Modeling><Molecular><Motor><Movement><Myosin ATPase><Myosin Adenosine Triphosphatase><Myosin Adenosinetriphosphatase><Myosins><Neocortex><Neoplasm Metastasis><Neural Stem Cell><Nexus Junction><Nuclear><Nuclear Lamin><Nucleus><Oocytes><Organ Culture><Organ Culture Techniques><Organelles><Ovary><Ovocytes><Pancreas Cancer><Pancreatic Cancer><Pathway interactions><Pb element><Phenotype><Plasma Membrane><Play><Post-Translational Modification Protein/Amino Acid Biochemistry><Post-Translational Modifications><Post-Translational Protein Modification><Post-Translational Protein Processing><Posttranslational Modifications><Posttranslational Protein Processing><Process><Protein Modification><Proteins><Pulmonary Cancer><Pulmonary malignant Neoplasm><Resolution><Role><Secondary Neoplasm><Secondary Tumor><Shapes><Site><Source><Surface><Systematics><Techniques><Testing><Text><Texture><Tissues><Type V IF Protein><Work><Wound Repair><active followup><body movement><cancer cell><cancer metastasis><cell behavior><cell motility><cellular behavior><developmental><driving><epithelial to mesenchymal transition><flexibility><flexible><follow up><follow-up><followed up><followup><fruit fly><gain of function><gene manipulation><genetic manipulation><genetically manipulate><genetically perturb><heavy metal Pb><heavy metal lead><homotypical cortex><imaging><in vitro Organ Culturing><in vitro vertebrate organ culturing><in vivo><in vivo Model><in vivo evaluation><in vivo testing><innovate><innovation><innovative><insight><intracellular skeleton><isocortex><loss of function><lung cancer><lung metastasis><lymphatic fluid><malignancy><mechanic><mechanical><membrane structure><metastasize to the lung><migration><neopallium><neoplasm/cancer><nerve stem cell><neural precursor><neural precursor cell><neural progenitor><neural progenitor cells><neuron progenitors><neuronal progenitor><neuronal progenitor cells><neuronal stem cells><neuroprogenitor><novel><optogenetics><pancreatic malignancy><pathway><plasmalemma><programs><pulmonary metastasis><recruit><resolutions><rho><rho G-Proteins><rho GTP-Binding Proteins><rho GTPases><rho Protein P21><rho Small GTP-Binding Proteins><social role><tissue repair><tumor><tumor cell metastasis><wound healing><wound recovery><wound resolution>