Imaging cellular and molecular processes driving cell migration during development

Cell movements play a central role throughout vertebrate embryogenesis. Migration is as fundamental a feature in proper development as proliferation, differentiation, and apoptosis. Yet less is known about cell migration patterns and the molecular mechanisms that govern them then about other aspects of development. By nature, the study of cell migration requires combined knowledge of anatomical landmarks and dynamic migratory patterns. An understanding of such dynamic processes is essential to integrate our increasingly detailed knowledge of genetic regulatory networks into the context of cellular interactions and morphogenesis. Recent technological advances have opened up an exciting new era in developmental biology where we can now address in detail and in real-time how cell behaviour governs the development of the embryo. Our groups are examining such intricately choreographed processes in distinct yet overlapping systems, such as the early mammalian embryo and in the mid-gestation to adult vertebrate nervous system. In order to be able to investigate such cell behaviour in the 3-dimensional context of the organism, we require a microscope with the ability to optically section our samples and obtain high resolution images. Furthermore we require a microscope that can do this over time, as development occurs over time. The state-of-the art equipment requested in this proposal would fulfill these requirements and enable us to achieve our objectives which address fundamental questions about the development of the adult form.

The Begbie group study sensory ganglia development. The process of forming the cranial sensory ganglia involves the migration of neuroblasts from neurogenic placodes in the surface ectoderm into the embryo. The Begbie group will use genetic constructs in collaboration with the Srinivas lab to characterize the behaviour and mode of neuroblast migration. Further they will determine how this process is coordinated with and by the neural crest cells. The Molnár group studies the migration dynamics of corticofugally projecting subplate neurons using a GFP transgenic mouse line to mark subplate cells and their projections in sub and intracortical circuits during early postnatal development. This group hopes to understand the molecular and cellular mechanisms of neuronal migration and links to human disorders. This work depends on comparing the timing and pattern of migration exhibited by various types of neurons. The Srinivas group studies the molecular and cellular basis for the migration of the AVE, a tissue that specifies and positions the anterior CNS. The group is also conducting a non-invasive lineage analysis of embryonic cells during gastrulation and cardiogenesis using a genetic lineage labeling system and using KikGR mice (a photoconvertable fluorescent protein). The Srinivas group is also generating reporter strains of mice expressing fluorescent Ca2+ reporters to study various roles of this important second messenger in development. The Szele group works on stem cells, neurogenesis, and migration in the postnatal mammalian subventricular zone (SVZ). Using high resolution confocal imaging, the Szele group studies the anatomical localization of subfields and subtypes of cells involved in adult neurogenesis. Using this approach, this group has discovered new patterns of newborn neuron migration. The experiments proposed by this group will determine cellular rules and moleculuar mechanisms that are important for regulating SVZ cell migration.