Invited Talk

A Positive Feedback Loop between Mesendoderm Cell Migration and Interstitial Fluid Relocalization is Required for Embryonic Axis Formation in Zebrafish

Carl-Philipp Heisenberg, Huljev Karla

ISTA, Am Campus 1, 3400 Klosterneuburg, Austria

Contact:  | Website

Accumulation of interstitial fluid (IF) between embryonic cells is a common phenomenon in vertebrate embryogenesis. IF has long been speculated to play a role in embryo patterning and morphogenesis, but direct evidence supporting such functions is still sparse. Here we show that the relocalization and accumulation of IF ahead of the migrating anterior axial mesendoderm (prechordal plate, ppl) is critical for ppl cell protrusion formation and migration, a key process in embryonic axis formation. We further show that ppl cell migration and IF accumulation are engaged in a positive mechanical feedback loop, where internalized ppl tissue, moving in between the epiblast and yolk cell, compress the overlying epiblast tissue, causing IF to relocate from the epiblast surface to the epiblast-yolk cell interface directly ahead of the advancing ppl. This accumulation of IF, in turn, facilitates ppl cell protrusion formation and migration by opening up the space into which the ppl moves, and thus the ability of the ppl to trigger the relocalization of IF by pushing against the overlying epiblast. Thus, embryonic axis formation relies on a positive mechanical feedback loop between tissue movement and IF relocalization.