RESUMO
Zebrafish E-cadherin (cdh1) cell adhesion molecule cDNAs were cloned. We investigated spatial and temporal expression of cdh1 during early embryogenesis. Expression was observed in blastomeres, the anterior mesoderm during gastrulation, and developing epithelial structures. In the developing nervous system, cdh1 was detected at the pharyngula stage (24 hpf) in the midbrain-hindbrain boundary (MHB). Developmental regulation of MHB formation involves wnt1 and pax2.1. wnt1 expression preceded cdh1 expression during MHB formation, and cdh1 expression in the MHB was dependent on normal development of this structure.
Assuntos
Encéfalo/embriologia , Caderinas/biossíntese , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica , Nucleotidiltransferases/metabolismo , Animais , Northern Blotting , DNA Complementar/metabolismo , Proteínas de Ligação a DNA/biossíntese , Proteínas Fúngicas/biossíntese , Biblioteca Gênica , Hibridização In Situ , Sistema Nervoso/embriologia , Nicotinamida-Nucleotídeo Adenililtransferase , Nucleotidiltransferases/genética , Fator de Transcrição PAX2 , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Transdução de Sinais , Fatores de Tempo , Distribuição Tecidual , Fatores de Transcrição/biossíntese , Peixe-Zebra , Proteínas de Peixe-ZebraRESUMO
Cadherins are homophilic cell adhesion molecules that control development of a variety of tissues and maintenance of adult structures. Although cadherins have been implicated in the development of the brain, including the visual system, in several vertebrate species, little is known of their role in zebrafish. In this study, we examined distribution of cadherin-2 (Cdh2, N-cadherin) in the visual system of developing and adult zebrafish using both immunocytochemical and in situ hybridization methods, and we compared Cdh2 distribution to that of the previously reported and closely related cadherin-4 (Cdh4, R-cadherin). As in other vertebrates, in zebrafish embryos Cdh2 was widely expressed in the early nervous system, but its expression became more restricted as development proceeded. Cdh4 was not detectable until later in development, at about the time when the first ganglion cells are generated. Cdh2 and Cdh4 were expressed in distinct regions of developing visual structures, including the lens. We hypothesize that the differential expression of these two cadherins in developing zebrafish visual structures reflects functionally different roles in the development of the vertebrate visual system.
