Abnormal retinal development in Cloche mutant zebrafish.
BACKGROUND
Functions for the early embryonic vasculature in regulating development of central nervous system tissues, such as the retina, have been suggested by in vitro studies and by in vivo manipulations that caused additional ocular vessels to develop. Here, we use an avascular zebrafish embryo, cloche-/- (clo-/-), to begin to identify necessary developmental functions of the ocular vasculature in regulating development and patterning of the neural retina, in vivo. These studies are possible in zebrafish embryos, which do not yet rely upon the vasculature for tissue oxygenation.


RESULTS
clo-/- embryos lacked early ocular vasculature and were microphthalmic, with reduced retinal cell proliferation and cell survival. Retinas of clo mutants were disorganized, with irregular synaptic layers, mispatterned expression domains of retinal transcription factors, morphologically abnormal Müller glia, reduced differentiation of specific retinal cell types, and sporadically distributed cone photoreceptors. Blockade of p53-mediated cell death did not completely rescue this phenotype and revealed ectopic cones in the inner nuclear layer. clo-/- embryos did not upregulate a molecular marker for hypoxia.


CONCLUSIONS
The disorganized retinal phenotype of clo-/- embryos is consistent with a neural and glial developmental patterning role for the early ocular vasculature that is independent of its eventual function in gas exchange.
Department of Biological Sciences, University of Idaho, Moscow, ID USA.|Neuroscience Graduate Program, University of Idaho, Moscow, ID USA.
Susov
S
Dhakal
Department of Biological Sciences, University of Idaho, Moscow, ID USA.
Craig B
CB
Stevens
Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Meyrav
M
Sebbagh
Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Omri
O
Weiss
Department of Biological Sciences, University of Idaho, Moscow, ID USA.
Ruth A
RA
Frey
Department of Biological Sciences, University of Idaho, Moscow, ID USA.
Seth
S
Adamson
Department of Molecular Biosciences, Washington State University, Pullman, WA USA.
Eric A
EA
Shelden
Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Adi
A
Inbal
Department of Biological Sciences, University of Idaho, Moscow, ID USA.|Neuroscience Graduate Program, University of Idaho, Moscow, ID USA.
Deborah L
DL
Stenkamp
D000818:Animals; D030801:Animals, Genetically Modified; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000502:physiology; D016923:Cell Death; D002454:Cell Differentiation; D049109:Cell Proliferation; D002470:Cell Survival; D004625:Embryo, Nonmammalian / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D000860:Hypoxia; D018613:Microscopy, Confocal; D009154:Mutation; D009457:Neuroglia / Q000502:physiology; D009474:Neurons / Q000502:physiology; D010641:Phenotype; D012160:Retina / Q000002:abnormalities* / Q000196:embryology*; D055213:Retinal Pigment Epithelium / Q000378:metabolism; D013234:Stem Cells; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins / Q000235:genetics* / Q000502:physiology
D051792:Basic Helix-Loop-Helix Proteins; D029961:Zebrafish Proteins; C000609736:npas4l protein, zebrafish
Müller glia; neurod1; neurogenesis; pax6a; photoreceptors; retina; vasculature; zebrafish