Cell and Tissue Research

, Volume 327, Issue 2, pp 313–322

Ontogeny of the GnRH systems in zebrafish brain: in situ hybridization and promoter-reporter expression analyses in intact animals

  • Ori Palevitch
  • Katherine Kight
  • Eytan Abraham
  • Susan Wray
  • Yonathan Zohar
  • Yoav Gothilf
Regular Article

DOI: 10.1007/s00441-006-0279-0

Cite this article as:
Palevitch, O., Kight, K., Abraham, E. et al. Cell Tissue Res (2007) 327: 313. doi:10.1007/s00441-006-0279-0
  • 447 Downloads

Abstract

The ontogeny of two gonadotropin-releasing-hormone (GnRH) systems, salmon GnRH (sGnRH) and chicken GnRH-II (cGnRH-II), was investigated in zebrafish (Danio rerio). In situ hybridization (ISH) first detected sGnRH mRNA-expressing cells at 1 day post-fertilization (pf) anterior to the developing olfactory organs. Subsequently, cells were seen along the ventral olfactory organs and the olfactory bulbs, reaching the terminal nerve (TN) ganglion at 5–6 days pf. Some cells were detected passing posteriorly through the ventral telencephalon (10–25 days pf), and by 25–30 days pf, sGnRH cells were found in the hypothalamic/preoptic area. Continuous documentation in live zebrafish was achieved by a promoter-reporter expression system. The expression of enhanced green fluorescent protein (EGFP) driven by the sGnRH promoter allowed the earlier detection of cells and projections and the migration of sGnRH neurons. This expression system revealed that long leading processes, presumably axons, preceded the migration of the sGnRH neuron somata. cGnRH-II mRNA expressing cells were initially detected (1 day pf) by ISH analysis at lateral aspects of the midbrain and later on (starting at 5 days pf) at the midline of the midbrain tegmentum. Detection of red fluorescent protein (DsRed) driven by the cGnRH-II promoter confirmed the midbrain expression domain and identified specific hindbrain and forebrain cGnRH-II-cells that were not identified by ISH. The forebrain DsRed-expressing cells seemed to emerge from the same site as the sGnRH-EGFP-expressing cells, as revealed by co-injection of both constructs. These studies indicate that zebrafish TN and hypothalamic sGnRH cell populations share a common embryonic origin and migratory path, and that midbrain cGnRH-II cells originate within the midbrain.

Keywords

Gonadotropin-releasing hormone In situ hybridization Reporter protein Neuronal migration Danio rerio (Teleostei

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Ori Palevitch
    • 1
  • Katherine Kight
    • 3
  • Eytan Abraham
    • 3
  • Susan Wray
    • 4
  • Yonathan Zohar
    • 3
  • Yoav Gothilf
    • 2
  1. 1.Department of Zoology, George S. Wise Faculty of Life SciencesTel-Aviv UniversityTel AvivIsrael
  2. 2.Department of Neurobiochemistry, George S. Wise Faculty of Life SciencesTel Aviv UniversityTel AvivIsrael
  3. 3.Center of Marine BiotechnologyUniversity of Maryland Biotechnology InstituteBaltimoreUSA
  4. 4.National Institute of Neurological Disorders and Stroke, Cellular and Developmental Neurobiology SectionBethesdaUSA

Personalised recommendations