Zebrafish: an exciting model for investigating the spatio-temporal pattern of enteric nervous system development.
OBJECTIVE
Recently, the zebrafish (Danio rerio) has been shown to be an excellent model for human paediatric research. Advantages over other models include its small size, externally visually accessible development and ease of experimental manipulation. The enteric nervous system (ENS) consists of neurons and enteric glia. Glial cells permit cell bodies and processes of neurons to be arranged and maintained in a proper spatial arrangement, and are essential in the maintenance of basic physiological functions of neurons. Glial fibrillary acidic protein (GFAP) is expressed in astrocytes, but also expressed outside of the central nervous system. The aim of this study was to investigate the spatio-temporal pattern of GFAP expression in developing zebrafish ENS from 24 h post-fertilization (hpf), using transgenic fish that express green fluorescent protein (GFP).


METHODS
Zebrafish embryos were collected from transgenic GFP Tg(GFAP:GFP)(mi2001) adult zebrafish from 24 to 120 hpf, fixed and processed for whole mount immunohistochemistry. Antibodies to Phox2b were used to identify enteric neurons. Specimens were mounted on slides and imaging was performed using a fluorescent laser confocal microscope.


RESULTS
GFAP:GFP labelling outside the spinal cord was identified in embryos from 48 hpf. The patterning was intracellular and consisted of elongated profiles that appeared to migrate away from the spinal cord into the periphery. At 72 and 96 hpf, GFAP:GFP was expressed dorsally and ventrally to the intestinal tract. At 120 hpf, GFAP:GFP was expressed throughout the intestinal wall, and clusters of enteric neurons were identified using Phox2b immunofluorescence along the pathway of GFAP:GFP positive processes, indicative of a migratory pathway of ENS precursors from the spinal cord into the intestine.


CONCLUSIONS
The pattern of migration of GFAP:GFP expressing cells outside the spinal cord suggests an organized, early developing migratory pathway to the ENS. This shows for the first time that Tg(GFAP:GFP)(mi2001) zebrafish model is an ideal one to study spatio-temporal patterning of early ENS development.
Doodnath
Reshma
R
National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin 12, Ireland. rdoodnath@gmail.com
Dervan
Adrian
A
Wride
Michael A
MA
Puri
Prem
P
D000818:Animals; D030801:Animals, Genetically Modified; D002465:Cell Movement; D017615:Enteric Nervous System / Q000196:embryology*; D005455:Fluorescent Antibody Technique; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D018398:Homeodomain Proteins; D006801:Humans; D014157:Transcription Factors; D015027:Zebrafish
D005904:Glial Fibrillary Acidic Protein; D018398:Homeodomain Proteins; C109220:NBPhox protein; D014157:Transcription Factors