@article {967,
	title = {Ras1 and a putative guanine nucleotide exchange factor perform crucial steps in signaling by the sevenless protein tyrosine kinase.},
	journal = {Cell},
	volume = {67},
	year = {1991},
	month = {1991 Nov 15},
	pages = {701-16},
	abstract = {<p>We have conducted a genetic screen for mutations that decrease the effectiveness of signaling by a protein tyrosine kinase, the product of the Drosophila melanogaster sevenless gene. These mutations define seven genes whose wild-type products may be required for signaling by sevenless. Four of the seven genes also appear to be essential for signaling by a second protein tyrosine kinase, the product of the Ellipse gene. The putative products of two of these seven genes have been identified. One encodes a ras protein. The other locus encodes a protein that is homologous to the S. cerevisiae CDC25 protein, an activator of guanine nucleotide exchange by ras proteins. These results suggest that the stimulation of ras protein activity is a key element in the signaling by sevenless and Ellipse and that this stimulation may be achieved by activating the exchange of GTP for bound GDP by the ras protein.</p>
},
	keywords = {Amino Acid Sequence, DNA Mutational Analysis, Drosophila Proteins, Eye Proteins, Genes, GTP-Binding Proteins, Guanine Nucleotide Exchange Factors, Membrane Glycoproteins, Molecular Sequence Data, Photoreceptor Cells, Protein-Tyrosine Kinases, Proteins, Proto-Oncogene Proteins p21(ras), ras Guanine Nucleotide Exchange Factors, Receptor Protein-Tyrosine Kinases, Restriction Mapping, Saccharomyces cerevisiae, Schizosaccharomyces, Sequence Alignment, Signal Transduction, Structure-Activity Relationship},
	issn = {0092-8674},
	doi = {10.1186/gb-2007-8-7-r145},
	author = {Simon, M A and Bowtell, D D and Dodson, G S and Laverty, T R and Rubin, G M}
}
@article {974,
	title = {Localization of the sevenless protein, a putative receptor for positional information, in the eye imaginal disc of Drosophila.},
	journal = {Cell},
	volume = {51},
	year = {1987},
	month = {1987 Oct 9},
	pages = {143-50},
	abstract = {<p>The Drosophila gene sevenless encodes a putative trans-membrane receptor required for the formation of one particular cell, the R7 photoreceptor, in each ommatidium of the compound eye. Mutations in this gene result in the cell normally destined to form the R7 cell forming a non-neuronal cell type instead. These observations have led to the proposal that the sevenless protein receives at least part of the positional information required for the R7 developmental pathway. We have generated antibodies specific for sevenless and have examined expression of the protein by light and electron microscopy. sevenless protein is present transiently at high levels in at least 9 cells in each developing ommatidium and is detectable several hours before any overt differentiation of R7. The protein is mostly localized at the apices of the cells, in microvilli, but is also found deeper in the tissue where certain cells contact the R8 cell. This finding suggests that R8 expresses a ligand for the sevenless protein.</p>
},
	keywords = {Animals, Drosophila melanogaster, Electron, Epithelium, Eye, Eye Proteins, Histocytochemistry, Immunologic Techniques, Insect Hormones, Microscopy, Microvilli, Peptide Fragments, Photoreceptor Cells},
	issn = {0092-8674},
	doi = {10.1186/gb-2007-8-7-r145},
	author = {Tomlinson, A and Bowtell, D D and Hafen, E and Rubin, G M}
}
