RESUMO
In the Drosophila embryo, a subset of muscles require expression and function of the RYK subfamily RTK gene derailed (drl) for correct attachment. We have isolated a second RYK homolog, doughnut (dnt), from Drosophila. The DNT protein exhibits 60% amino acid identity to DRL, and is structurally as similar to the mammalian RYK proteins as is DRL, indicating an ancient duplication event. dnt is expressed in dynamic patterns in the embryonic epidermis, being found at high level in epithelia adjacent to cells that are invaginating into the interior of the embryo, including ventral furrow, cephalic furrow, fore- and hindgut, optic lobe and tracheal pits. dnt is capable of a partial rescue of the muscle attachment defect of drl-/- embryos, indicating that it encodes a receptor with a related and significantly overlapping biochemical function.
Assuntos
Proteínas de Drosophila , Drosophila melanogaster/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes de Insetos , Proteínas Musculares/biossíntese , Músculos/embriologia , Proteínas Tirosina Quinases/biossíntese , Sequência de Aminoácidos , Animais , Mapeamento Cromossômico , Clonagem Molecular , Drosophila melanogaster/embriologia , Epiderme/embriologia , Epiderme/metabolismo , Teste de Complementação Genética , Mamíferos/genética , Dados de Sequência Molecular , Morfogênese/genética , Proteínas Musculares/genética , Proteínas Musculares/fisiologia , Músculos/metabolismo , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/fisiologia , Receptores Proteína Tirosina Quinases/deficiência , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/fisiologia , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
During development, muscles must form and attach at highly stereotyped positions to allow for coordinated movements. In Drosophila, muscles grow towards and attach to specifically positioned cells within the epidermis. At the molecular level, very little is known about how muscles recognize these attachment sites. The derailed gene encodes a receptor tyrosine kinase family member that is essential for the pathfinding ability of expressing neurons. Here we show that the Drl RTK is also expressed by a small subset of developing embryonic muscles and neighboring epidermal cells during muscle attachment site selection. In drl mutants, these muscles often fail to attach at appropriate locations although their epidermal attachment cells appear unaffected. These results show that, similar to its role in neuronal pathway recognition, the Drl RTK participates in a mechanism required for muscle attachment site selection. The data suggest that both neurons and muscles use common mechanisms to recognize their paths or targets, and that Drl plays an analogous role in both developing systems.
