An adult stem-like cell population generates germline and neurons in the sea anemoneNematostella vectensis

Abstract

AbstractMost genetic research animals (e.g., vertebrates, insects, nematodes) segregate germline and soma during early embryogenesis. In contrast, some highly regenerative bilaterian (e.g., planarians) and non-bilaterian animals (e.g., hydrozoan cnidarians) retain adult stem cells with both germinal and somatic potentials. As these cells have been studied in only few phyla, their biology and evolution remain mostly enigmatic. Here, we aimed to identify and characterize adult stem cells and their cell lineages in the sea anemoneNematostella vectensisby combining gene expression analysis, immunostainings, and meganuclease-mediated and CRISPR/Cas9-mediated knock-in reporter lines of conserved germline and multipotency genes (e.g.,vasa2,piwi1). We found a small population ofvasa2+/piwi1+ cells in the gastrodermal folds of juvenile and adult sea anemones that generates germline and a diversity of somatic, mostly proliferative cells. Using a combination ofsoxB(2)neural progenitor andpiwi1reporter lines, we found that the somatic progeny fromvasa2+/piwi1+ cells includessoxB(2)+ neural progenitors. Our results strongly support the existence of an adult Vasa2+/Piwi1+ multipotent stem-like cell population that derives both germline and somatic lineages inNematostella. The similarities of lineages and gene expression profiles betweenNematostellaVasa2+/Piwi1+ stem-like cells and hydrozoan interstitial stem cells support their evolutionary conservation among cnidarians.