fezf2 expression delineates cells with proliferative potential and expressing markers of neural stem cells in the adult zebrafish brain.

Fezf2 (also known as Fezl, ZNF312, or Zfp312) is an evolutionarily conserved forebrain-specific zinc finger transcription factor that is expressed during development and is implicated in patterning as well as neurogenesis in both zebrafish and mice. Despite these findings, the expression of fezf2 in the adult brain has not been well characterized, and fezf2 function in the adult brain remains unknown. The zebrafish has recently emerged as a new model system to study adult neurogenesis, given its similarity to mammalian systems and enhanced capability of undergoing adult neurogenesis. Through RNA in situ hybridization and using a fezf2 promoter-driven GFP transgenic line, we present data showing that fezf2 is expressed in radial glial progenitor cells of the telencephalic ventricular zone in the adult zebrafish brain, which co-express markers of neural stem cells and proliferation. Additionally, we identify the preoptic region and the hypothalamus as fezf2-expressing neurogenic regions in the adult zebrafish brain, where fezf2 labels progenitor cells as well as postmitotic neurons. Our findings establish Fezf2 as a novel marker for adult telencephalic ventricular progenitor cells that express markers of neural stem cells in zebrafish and lay a critical foundation for future investigation of Fezf2 function in the maintenance and differentiation of neural stem cells in the adult vertebrate brain.