Move2Hatch · Evolution and Development of Hatching Gland in Teleost Fish

Hatching is a universal milestone in animal development, present in both oviparous and viviparous species. Biochemical hatching has been described for several species and most of the research has been focused on the enzymes secreted by unicellular glands. These hatching gland cells (HGCs) are typically non-migratory, but in teleost fishes, they acquired migratory capacity. This evolutionary novelty has enabled remarkable morphological diversification with ecological and behavioral consequences. Thus, the HG provides a unique opportunity to investigate how changes in cell migration drive developmental and evolutionary innovation. To address it, I will test in Move2Hatch the hypothesis that the local microenvironment plays a decisive role in HGCs' migratory behavior, shaping the gland morphogenesis. Three objectives are proposed using zebrafish and medaka as complementary teleost models. O1—Define cell-intrinsic migratory properties of HGCs: assess the HGC behaviors through distinct migratory microenvironments and quantify the variance attributable to intrinsic programs. O2—Identify molecular players regulating HG migration, combining a candidate-based approach with unbiased transcriptomic profiling to reveal molecules potentially mediating environment-specific migration. O3—Determine the biophysical properties of the HG and its migratory environment: quantify properties like adhesiveness and mechanical stress during in vivo migration, and perform experimental alterations of the stiffness of the migratory substrate. By linking cellular autonomy (O1), molecular regulation (O2), and biophysical context (O3) within a unified comparative framework, Move2Hatch will deliver achievable results as 4D imaging, cell tracking, and RNA profiles, as well as atomic force microscopy and microdroplet-based measurements. Move2Hatch will generate novel insights into HG biology while providing the host with a new model system and me with expertise in mechanobiology and cell biology.