Expression of zebrafish nk2.2 is influenced by sonic hedgehog/vertebrate hedgehog-1 and demarcates a zone of neuronal differentiation in the embryonic forebrain.
We have isolated zebrafish nk2.2, a member of the Nk-2 family of homeobox genes. nk2.2 is expressed in a continuous narrow band of cells along a boundary zone demarcating the location at which two of the earliest nuclei in the brain differentiate. This band of cells is located within a few cell diameters of cells expressing the signalling molecule sonic hedgehog/vertebrate hedgehog-1 (shh/vhh-1). Injection of shh/vhh-1 RNA results in ectopic expression of nk2.2 and concomitant abnormalities in the forebrain and eyes. Moreover, cyclops mutant embryos, which initially lack neurectodermal expression of shh/vhh-1, show a concomitant lack of nk2.2 expression. Together, these results suggest a requirement of shh/vhh-1 protein for the spatial regulation of nk2.2 expression.
Barth
K A
KA
Developmental Biology Research Centre, Randall Institute, King's College London, UK.
Wilson
S W
SW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000196:embryology*; D002454:Cell Differentiation; D005123:Eye / Q000196:embryology; D018507:Gene Expression Regulation, Developmental; D018014:Gene Transfer Techniques; D005801:Genes, Homeobox; D053823:Hedgehog Proteins; D000090322:Homeobox Protein Nkx-2.2; D018398:Homeodomain Proteins / Q000235:genetics*; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000502:physiology; D011506:Proteins / Q000235:genetics*; D015534:Trans-Activators; D015027:Zebrafish / Q000235:genetics*; D029961:Zebrafish Proteins
D053823:Hedgehog Proteins; D000090322:Homeobox Protein Nkx-2.2; D018398:Homeodomain Proteins; D011506:Proteins; D015534:Trans-Activators; D029961:Zebrafish Proteins