The Drosophila gene torso encodes a putative receptor tyrosine kinase

Sprenger, Frank; Stevens, Leslie M.; Nüsslein‐Volhard, Christiane

doi:10.1038/338478a0

Cited by 313 publications

(151 citation statements)

References 41 publications

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“…Similarly, mutations in another transmembrane protein tyrosine kinase, the Drosophila epidermal growth factor (EGF) receptor homolog (DER) gene, have been found to result in abnormal egg development (Price et al 1989;Schejter and Shilo 1989) and to affect differentiation of ommatidia in compound eye development (Baker and Rubin 1989). Torso, mutation of which affects pattern formation in the early Drosophila embryo, has also been shown to encode a receptor tyrosine kinase (Sprenger et al 1989).…”

mentioning

confidence: 99%

W mutant mice with mild or severe developmental defects contain distinct point mutations in the kinase domain of the c-kit receptor.

Reith¹,

Rottapel²,

Giddens³

et al. 1990

Genes Dev.

325

194

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Mutations at the mouse W/c-kit locus lead to intrinsic defects in stem cells of the melanocytic, hematopoietic, and germ cell lineages. W alleles vary in the overall severity of phenotype that they confer, and some alleles exhibit an independence of pleiotropic effects. To elucidate the molecular basis for these biological differences, we analyzed the c-k/t locus and the c-kit.associated autophosphorylation activities in five different W mutants representative of a range of W phenotypes. Mast cell cultures derived from mice or embryos homozygous for each W allele were deficient in c-kit autophosphorylation activity, the extent of which paralleled the severity of phenotype conferred by a given W allele both in vivo and in an in vitro mast cell coculture assay. The mildly dominant, homozygous viable alleles W 44 and W s7 were found to express reduced levels of an apparently normal c-k/t protein. In contrast, c-kit kinase defects conferred by the moderately dominant, homozygous viable alleles W 4~ or W ss or the homozygous lethal allele, W 37, were attributed to single-point mutations within the kinase domain of the c-kit polypeptide, which result in point substitutions of amino acid residues highly conserved in the family of protein tyrosine kinases. The nature and location of these amino acid substitutions account for the relative severity of phenotypes conferred by these W alleles and demonstrate that the pleiotropic developmental defects associated with the W/c-kit locus arise as the result of dominant loss-of-function mutations in a transmembrane receptor tyrosine kinase.

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mentioning

confidence: 99%

W mutant mice with mild or severe developmental defects contain distinct point mutations in the kinase domain of the c-kit receptor.

Reith¹,

Rottapel²,

Giddens³

et al. 1990

Genes Dev.

325

194

View full text Add to dashboard Cite

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“…The en expression patterns of embryos lacking tor activity (collected from homozygous torPM females) (10,11) and of embryos homozygous for the mutations hkb2 (12), croc5F59 (gift of G. Jurgens), Df(1)KA14 uncovering otd (13), ems9Q64 (14,15), btdXG (16), or Df(1)62gl8 uncovering gt (17,18) were analyzed (6,9,(13)(14)(15)(16)(17)(18)(19)(20)(21) by antibody staining of en-encoded protein (22); the sensory organs, sensory nerves, and the stomatogastric nervous system (SNS) were examined by 22C10 antibody staining (23). Examination ofwhole mount preparations of wild-type and mutant embryos was done as described (7,24).…”

mentioning

confidence: 99%

Number, identity, and sequence of the Drosophila head segments as revealed by neural elements and their deletion patterns in mutants.

Schmidt‐Ott

González‐Gaitán

Jäckle

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

103

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The development of the insect head tagma involves massive rearrangements and secondary fusions of segment anlagen during embryogenesis. Due to the lack of reliable morphological markers, the number, identity, and sequence of the head segments, particularly in the pregnathal region, are still a matter of ongoing debates. We examined the complex array of internal structures of the embryonic Drosophila melanogaster head such as the sensory structures and nerves of the peripheral and stomatogastric nervous systems, and we used embryonic head mutations causing a lack of overlapping segment anlagen to unravel the segmental identity and the sequence of the neural elements. Our results provide evidence for seven distinct segments in the Drosophila head, each characterized by a specific set of sensory neurons, consistent with the proposal that insects, myriapods, and crustaceans share a monophyletic evolutionary tree from a common annelid-like ancestor.The insect body is composed of metamerically repeated units. While segmentation is obvious in the "trunk" region, the segmental organization of the head is still obscure (1-7). By distinct cuticular features, three gnathal segments (mandibula, maxilla, and labium) can be distinguished in the posterior head region. The anterior pregnathal region, however, is poor in diagnostic morphological structures (8). Morphological and evolutionary studies based on epidermal head structures (5, 8), coelomic cavities, or brain regions (1-4) have so far failed to unambiguously determine the number and identity of pregnathal segments in the insect head. Due to the evolutionary changes that resulted in the "acephalic" appearance of higher dipteran larvae, the segmental composition of the Drosophila head was analyzed only recently. The detailed fate map analysis of a few cuticular specializations of the larval Drosophila head by laser ablation studies suggested six segments-i.e., three pregnathal and three gnathal segments (5). This interpretation was questioned through a detailed analysis of the expression patterns of the segment polarity genes engrailed (en) and wingless (wg), which serve as molecular markers for metamers in the prospective trunk and gnathal regions of the Drosophila embryo. This analysis suggested the possibility of seven instead of only six head segments (7). Here we present additional and more substantial evidence for seven head segments which is based on detailed analysis of internal head structures such as sensory organs. Their axons fasciculate to give rise to seven distinct sensory projections to the brain. The analysis of the patterns of sense organs deleted in various head segmentation mutants allows us to make an assignment of the sense organs to their segments of origin.MATERIALS AND METHODS Drosophila melanogaster strains were kept under standard conditions; wild-type and mutant embryos were obtained as described (9). The en expression patterns of embryos lacking tor activity (collected from homozygous torPM females) (10, 11) and of embryos homozygous ...

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“…As in the case of the sev receptor, other tyrosine kinase receptors with widespread distributions are only locally activated during development. For instance, the Diosophila gene product torso, predicted to encode a membrane-bound tyrosine kinase (Sprenger et al 1989), is uniformly distributed along the surface of the early embryo but is active only at the termini (Casanova and Struhl 1989). It has been speculated that this activation is the result of selective localization of the ligand to the anterior and posterior poles of the embryo.…”

Section: Discussionmentioning

confidence: 99%

Induction of cell fate in the Drosophila retina: the bride of sevenless protein is predicted to contain a large extracellular domain and seven transmembrane segments.

et al. 1990

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Previous genetic mosaic studies established that expression of the Drosophila bride of sevenless (boss) gene is required in photoreceptor neuron R8 for the development of photoreceptor neuron R7. This led to the proposal that boss encodes or regulates an R7-specific inductive cue. We have identified the boss gene based on small deletions in mutant alleles and sequenced both cDNAs and corresponding genomic regions. One P element and three X-ray-induced boss alleles show different deletions in the gene ranging in size from 2 to 23 bp, each causing frameshifts leading to premature termination of translation. The boss gene encodes a protein of 896 amino acids with a putative amino-terminal signal sequence, a large extracellular region of 498 amino acids, and seven potential transmembrane domains followed by a carboxy-terminal cytoplasmic tail of 115 amino acids. The putative membrane localization of the boss protein is consistent with a model in which direct interaction between the boss and sevenless proteins specifies R7 cell fate. Another model in which the boss protein functions as a receptor is proposed based on its similarity to the G protein-linked family of membrane receptors.

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The Drosophila gene torso encodes a putative receptor tyrosine kinase

Cited by 313 publications

References 41 publications

W mutant mice with mild or severe developmental defects contain distinct point mutations in the kinase domain of the c-kit receptor.

W mutant mice with mild or severe developmental defects contain distinct point mutations in the kinase domain of the c-kit receptor.

Number, identity, and sequence of the Drosophila head segments as revealed by neural elements and their deletion patterns in mutants.

Induction of cell fate in the Drosophila retina: the bride of sevenless protein is predicted to contain a large extracellular domain and seven transmembrane segments.

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