Single-cell analysis reveals functionally distinct classes within the planarian stem cell compartment

Cell Stem Cell. 2014 Sep 4;15(3):326-339. doi: 10.1016/j.stem.2014.06.007. Epub 2014 Jul 10.


Planarians are flatworms capable of regenerating any missing body region. This capacity is mediated by neoblasts, a proliferative cell population that contains pluripotent stem cells. Although population-based studies have revealed many neoblast characteristics, whether functionally distinct classes exist within this population is unclear. Here, we used high-dimensional single-cell transcriptional profiling from over a thousand individual neoblasts to directly compare gene expression fingerprints during homeostasis and regeneration. We identified two prominent neoblast classes that we named ζ (zeta) and σ (sigma). Zeta-neoblasts encompass specified cells that give rise to an abundant postmitotic lineage, including epidermal cells, and are not required for regeneration. By contrast, sigma-neoblasts proliferate in response to injury, possess broad lineage capacity, and can give rise to zeta-neoblasts. These findings indicate that planarian neoblasts comprise two major and functionally distinct cellular compartments.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers / metabolism
  • Cell Compartmentation*
  • Cell Cycle
  • Cell Lineage
  • Epidermal Cells
  • Gene Expression Profiling
  • Planarians / cytology*
  • Pluripotent Stem Cells / cytology
  • RNA Interference
  • Regeneration
  • Single-Cell Analysis / methods*
  • Stem Cells / cytology*


  • Biomarkers