Ocular and cerebellar defects in zebrafish induced by overexpression of the LIM domains of the islet-3 LIM/homeodomain protein.
Islet-3 is an LIM/homeodomain protein that is expressed specifically in the eyes and the presumptive tectum in the central nervous system of zebrafish (Danio rerio) embryos. Overexpression of the protein (LIM(Isl-3)) consisting only of the Islet-3 LIM domains in embryos specifically prevented formation of the optic vesicles; caused abnormal termination of the expression of wnt1, engrailed2, and pax2 in the mesencephalic and metencephalic region between 14 hr and 20 hr postfertilization; and severely impaired morphogenetic movement in this region between 20 hr and 26 hr, which should normally lead to formation of the cerebellar primordium. Such defects were all rescued by simultaneous overexpression of Islet-3, suggesting that LIM(Isl-3) acted as a specific dominant-negative variant of Islet-3. These data, combined with the results of mosaic analyses, suggest that Islet-3 is activated by putative LIM-binding cofactors and functions to promote evagination of the optic vesicles and to maintain reciprocal interaction between the mesencephalon and the mesencephalic-metencephalic boundary essential for normal development of this region.
Kikuchi
Y
Y
Department of Physiology, Keio University, School of Medicine, Shinjuku, Tokyo, Japan.
Segawa
H
H
Tokumoto
M
M
Tsubokawa
T
T
Hotta
Y
Y
Uyemura
K
K
Okamoto
H
H
D000818:Animals; D002531:Cerebellum / Q000002:abnormalities* / Q000196:embryology; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000002:abnormalities; D005124:Eye Abnormalities / Q000196:embryology / Q000235:genetics*; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D017403:In Situ Hybridization; D060850:LIM-Homeodomain Proteins; D009024:Morphogenesis; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D051762:PAX2 Transcription Factor; D010446:Peptide Fragments / Q000096:biosynthesis / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D051153:Wnt Proteins; D051155:Wnt1 Protein; D015027:Zebrafish / Q000235:genetics / Q000502:physiology*; D029961:Zebrafish Proteins; D000099266:Engrailed 2 Protein
D004268:DNA-Binding Proteins; D005136:Eye Proteins; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; D009419:Nerve Tissue Proteins; D051762:PAX2 Transcription Factor; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029961:Zebrafish Proteins; C079428:en2a protein, zebrafish; D000099266:Engrailed 2 Protein; C063843:insulin gene enhancer binding protein Isl-1; C558563:isl2b protein, zebrafish; C497320:pax2a protein, zebrafish; C094522:wnt8b protein, zebrafish