Dynamic fate map of hindbrain rhombomeres in zebrafish

Abstract

Understanding of the morphogenetic processes that underlie the patterning of the vertebrate hindbrain requires establishment of rhombomere (r) cell lineages. Using long term in vivo two-photon imaging of zebrafish transgenic lines and automated image processing tools, we provide a method to reconstruct the r2-r6 lineage trees from the onset of gastrulation through early neurulation. We provide a dynamic fate map of hindbrain patterning at single-cell resolution. We show that rhombomere progenitor domains are aligned along the anteroposterior (AP) and dorsoventral (DV) axes as early as the shield stage. Rhombomere progenitor domains show a segmental organization, parallel to the blastoderm margin that predicts the future AP order of hindbrain. The DV organization of rhombomeres is set by the segregation of the progenitors along the DV axis of the embryo. Progenitors located at the dorsal/medial part of the blastoderm form the ventral domain of the rhombomeres while the lateral progenitors constitute the dorsal part. Our study sheds light on the clonal origin of individual rhombomeres, spatial and temporal patterns of cell division and migration of rhombomere progenitors throughout the early steps of hindbrain morphogenesis.