Impaired neural development in a zebrafish model for Lowe syndrome.
Lowe syndrome, which is characterized by defects in the central nervous system, eyes and kidneys, is caused by mutation of the phosphoinositide 5-phosphatase OCRL1. The mechanisms by which loss of OCRL1 leads to the phenotypic manifestations of Lowe syndrome are currently unclear, in part, owing to the lack of an animal model that recapitulates the disease phenotype. Here, we describe a zebrafish model for Lowe syndrome using stable and transient suppression of OCRL1 expression. Deficiency of OCRL1, which is enriched in the brain, leads to neurological defects similar to those reported in Lowe syndrome patients, namely increased susceptibility to heat-induced seizures and cystic brain lesions. In OCRL1-deficient embryos, Akt signalling is reduced and there is both increased apoptosis and reduced proliferation, most strikingly in the neural tissue. Rescue experiments indicate that catalytic activity and binding to the vesicle coat protein clathrin are essential for OCRL1 function in these processes. Our results indicate a novel role for OCRL1 in neural development, and support a model whereby dysregulation of phosphoinositide metabolism and clathrin-mediated membrane traffic leads to the neurological symptoms of Lowe syndrome.
University of Manchester, The Michael Smith Building, Manchester M13 9PT, UK.
Irene Barinaga-Rementeria
IB
Ramirez
Grzegorz
G
Pietka
David R
DR
Jones
Nullin
N
Divecha
A
A
Alia
Scott C
SC
Baraban
Adam F L
AF
Hurlstone
Martin
M
Lowe
D000818:Animals; D001921:Brain / Q000196:embryology* / Q000473:pathology; D002470:Cell Survival; D002966:Clathrin / Q000378:metabolism; D004195:Disease Models, Animal; D004625:Embryo, Nonmammalian; D047108:Embryonic Development; D011992:Endosomes / Q000378:metabolism; D020869:Gene Expression Profiling; D006056:Golgi Apparatus / Q000378:metabolism; D006358:Hot Temperature; D009800:Oculocerebrorenal Syndrome; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics* / Q000378:metabolism; D019154:Protein Splicing; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012640:Seizures / Q000503:physiopathology; D015398:Signal Transduction; D015027:Zebrafish / Q000196:embryology / Q000235:genetics / Q000254:growth & development; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism; D000099182:Phosphoinositide 5-Phosphatases
D002966:Clathrin; D019269:Phosphatidylinositol 4,5-Diphosphate; D010744:Phosphoric Monoester Hydrolases; D051057:Proto-Oncogene Proteins c-akt; D029961:Zebrafish Proteins; D000099182:Phosphoinositide 5-Phosphatases; C576582:ocrl protein, zebrafish