Scientific article
Open access

The Wnt/β-catenin/TCF/Sp5/Zic4 Gene Network That Regulates Head Organizer Activity in Hydra Is Differentially Regulated in Epidermis and Gastrodermis

Published inBiomedicines, vol. 12, no. 6, 1274
Publication date2024-06-08
First online date2024-06-08

Hydra head formation depends on an organizing center in which Wnt/β-catenin signaling, that plays an inductive role, positively regulates Sp5 and Zic4, with Sp5 limiting Wnt3/β-catenin expression and Zic4 triggering tentacle formation. Using transgenic lines in which the HySp5 promoter drives eGFP expression in either the epidermis or gastrodermis, we show that Sp5 promoter activity is differentially regulated in each epithelial layer. In intact animals, epidermal HySp5:GFP activity is strong apically and weak along the body column, while in the gastrodermis, it is maximal in the tentacle ring region and maintained at a high level along the upper body column. During apical regeneration, HySp5:GFP is activated early in the gastrodermis and later in the epidermis. Alsterpaullone treatment induces a shift in apical HySp5:GFP expression towards the body column where it forms transient circular figures in the epidermis. Upon β-catenin(RNAi), HySp5:GFP activity is down-regulated in the epidermis while bud-like structures expressing HySp5:GFP in the gastrodermis develop. Sp5(RNAi) reveals a negative Sp5 autoregulation in the epidermis, but not in the gastrodermis. These differential regulations in the epidermis and gastrodermis highlight the distinct architectures of the Wnt/β-catenin/TCF/Sp5/Zic4 network in the hypostome, tentacle base and body column of intact animals, as well as in the buds and apical and basal regenerating tips.

  • Hydra head organizer
  • Hydra transgenic lines
  • Epidermal and gastrodermal epithelial layers
  • Sp5 transcription factor
  • Sp5 promoter autoregulation
  • Zic4 transcription factor
  • Zic4 tentacle regulator
  • Wnt/ β -catenin signaling
  • Gene regulatory network (GRN)
  • HEK293T mammalian cells
Research group
Citation (ISO format)
IGLESIAS OLLE, Laura et al. The <i>Wnt/β-catenin/TCF/Sp5/Zic4</i> Gene Network That Regulates Head Organizer Activity in <i>Hydra </i>Is Differentially Regulated in Epidermis and Gastrodermis. In: Biomedicines, 2024, vol. 12, n° 6, p. 1274. doi: 10.3390/biomedicines12061274
Main files (2)
Article (Published version)
Article (Published version) - supplementary data
ISSN of the journal2227-9059

Technical informations

Creation06/11/2024 8:24:41 AM
First validation06/11/2024 9:33:11 AM
Update time06/11/2024 9:33:11 AM
Status update06/11/2024 9:33:11 AM
Last indexation06/11/2024 9:33:32 AM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack