Patterning and morphogenesis of the intricate but stereotyped oikoplastic epidermis of the appendicularian, Oikopleura dioica.

摘要: Mechanisms for morphogenetic processes that generate complex patterns in a reproducible manner remain elusive. Live imaging provides powerful tool to record cell behaviors. The appendicularian, Oikopleura dioica, is planktonic tunicate has rapid developmental speed, small number of cells (less than 3500 juvenile), and transparent body. trunk epidermis, called the oikoplastic epithelium (OE), elaborate cellular arrangements showing pattern secrete so-called "house" made extracellular components. OE characterized by invariant number, size, shape monolayer epithelial cells. Pattern formation achieved during 5h larval development without growth body, making this suitable system live two-dimensional (2D) sheet. First, we subdivided defined several domains resolution, systematically gave names constituent cells, since there no variation among individuals. Time-lapse epidermal revealed region-specific processes. Each identified domain served as compartment into which distribution descendant founder restricted. Regulation orientation, timing, rounds divisions, but not death migration, was critical mechanism determination final arrangement size. In addition, displacement sheet plates observed Eisen domain. Stem-cell-like whereby large mother stem chain daughter were involved Nasse region ventral sensory organ. These are first examples kind stem-cell-like division deuterostomes. Furthermore, labeling left or right blastomere two-cell-stage embryo, roughly gives rise side respectively, boundary does match with midline epidermis. Left descendants largely invade opposite an way, suggesting possibility specification identities may occur later development, most probably around hatching, depending on position detailed descriptions patterning provide basic essential information analyze further behaviors generation intricate stereotyped 2D advantageous model biological studies chordates.