The sevenless+ protein is expressed apically in cell membranes of developing Drosophila retina; it is not restricted to cell R7

Banerjee, Utpal; Renfranz, Patricia J.; Hinton, David R.; Rabin, Bruce A.; Benzer, Seymour

doi:10.1016/0092-8674(87)90020-1

Cited by 122 publications

(64 citation statements)

References 19 publications

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“…Such a protein would be well suited for transducing a signal required for R7 differentiation by activation of its intracellular kinase domain in response to binding of a ligand to its extracellular domain. The observation that sevenless protein is expressed in the pre-R7 cell prior to any morphological signs of photoreceptor differentiation is consistent with a role for the sevenless protein in transducing a signal that specifies the R7 fate (11,12). …”

mentioning

confidence: 56%

Structure and activity of the sevenless protein: a protein tyrosine kinase receptor required for photoreceptor development in Drosophila.

Simon

Bowtell

Rubin

1989

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

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The sevenless gene encodes a putative protein tyrosine kinase receptor that is required for the proper differentiation of the R7 photoreceptor cells of the Drosophila eye. We have expressed the sevenless protein in Drosophila tissue culture cells and studied its synthesis, processing, and activity. Our results show that the sevenless protein possesses protein tyrosine kinase activity. The protein is first synthesized as a 280-kDa glycoprotein precursor that is subsequently cleaved into 220-kDa amino-terminal and 58-kDa carboxyl-terminal subunits that remain associated by noncovalent interactions. The 220-kDa subunit is glycosylated and contains most of the extracellular portion of the protein, and the 58-kDa subunit is composed of a small portion of the extracellular sequences and the intracellular protein tyrosine kinase domain. This complex is subsequently cleaved into either 49-or 48-kDa carboxylterminal fragments with concomitant degradation of the rest of the protein.The Drosophila compound eye consists of several hundred identical subunits, called ommatidia. Each ommatidium is composed of 8 photoreceptor cells and 12 non-neuronal accessory cells. This precise array of cells develops from an initially unpatterned epithelium during the last larval instar and pupal periods (1, 2). Cells are instructed to appropriate differentiation pathways by signals produced by neighboring cells (3) in a process of progressive recruitment that is not dependent on cell lineage (1, 4). Studies of the nature of these signals and their receptors are crucial to understanding how the eye develops.Mutations that inactivate the sevenless gene cause a single cell, the photoreceptor R7, to be absent from each ommatidium (5). A cell occupies the proper position to become R7 in the developing ommatidium but becomes a lens-secreting cell rather than a photoreceptor cell (6). Studies of ommatidia mosaic for sevenless function have demonstrated that the sevenless gene product is required only in the developing R7 cell (5-7). Thus these observations suggested that the sevenless gene product is required either for the reception of a signal that acts to help specify the fate of the R7 cell or for the proper execution of the pathway that leads to R7 development.Conceptual translation of sevenless cDN-As (8-10) predicts a 288-kDa membrane protein with a large extracellular domain and a cytoplasmic domain possessing extensive homology to protein tyrosine kinases. Such a protein would be well suited for transducing a signal required for R7 differentiation by activation of its intracellular kinase domain in response to binding of a ligand to its extracellular domain. The observation that sevenless protein is expressed in the pre-R7 cell prior to any morphological signs of photoreceptor differentiation is consistent with a role for the sevenless protein in transducing a signal that specifies the R7 fate (11,12).An understanding of the structure and activity of the sevenless protein is a prerequisite for understanding the molecular mechanis...

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mentioning

confidence: 56%

Structure and activity of the sevenless protein: a protein tyrosine kinase receptor required for photoreceptor development in Drosophila.

Simon

Bowtell

Rubin

1989

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

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“…1 c and i). Moreover, the staining was restricted to the part of the disc where ommatidial development had commenced, consistent with the localization of sevenless mRNA and protein (9,10,13,14). In contrast, none of the lines in which sequences from the remainder of the gene (fragment 2) were placed 5' of the -967/IacZ construct showed any /3-galactosidase activity.…”

Section: Sevenless Transcription Unit Results and Discussionmentioning

confidence: 74%

“…According to Tomlinson et al (13) sevenless protein is expressed transiently in the presumptive photoreceptor cells R3, R4, and R7, in two cells of unknown developmental fate called mystery cells, and in the cells that ultimately produce the lens, the cone cells. In contrast, Banerjee et al (14) reported that sevenless protein is expressed in all, rather than a subset of, photoreceptors and in the cone cells.…”

mentioning

confidence: 97%

“…The distribution of sevenless protein in the eye disc has been independently investigated by two groups (13,14). According to Tomlinson et al (13) sevenless protein is expressed transiently in the presumptive photoreceptor cells R3, R4, and R7, in two cells of unknown developmental fate called mystery cells, and in the cells that ultimately produce the lens, the cone cells.…”

mentioning

confidence: 99%

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Regulation of the complex pattern of sevenless expression in the developing Drosophila eye.

Bowtell

Kimmel²,

Simon³

et al. 1989

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

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“…2B). This enhancer is active transiently in subsets of cells in the developing eye Bowtell et al, 1989) and subsequently in adult heads, but is not known to be expressed in any other tissue or at any other stage of development Banerjee et al, 1987aBanerjee et al, , 1987bHafen et al, 1987). Hence, disruption of sev-expressing cells should be easily detectable and should not affect survival to adulthood.…”

Section: Transforming Drosophila With Rats Mutant Genesmentioning

confidence: 99%

Inducible cell ablation in Drosophila by cold-sensitive ricin A chain

1992

Trends in Genetics

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SummaryWe have developed a system for temperature-inducible killing of specific cells in the fruitfly Drosophila melanogaster. The system overcomes many of the limitations of existing cell ablation methods and is in principle applicable to any non-homeothermic eukaryote. Temperature-sensitive and cold-sensitive mutations in the ricin toxin A chain (RTA) of castor bean were generated in yeast. One cold-sensitive mutation, RAcs2, produced temperature-dependent ablation of eye cells in Drosophila when expressed under control of the eye-specific sev enhancer. At 29°C, cell death was observed within 7 hours in the developing eye and no obvious toxic effects were observed elsewhere; at 18°C, extremely low toxicity was observed. DNA sequencing of RAcs2 revealed a single amino acid substitution in the RTA active site cleft.

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The sevenless+ protein is expressed apically in cell membranes of developing Drosophila retina; it is not restricted to cell R7

Cited by 122 publications

References 19 publications

Structure and activity of the sevenless protein: a protein tyrosine kinase receptor required for photoreceptor development in Drosophila.

Structure and activity of the sevenless protein: a protein tyrosine kinase receptor required for photoreceptor development in Drosophila.

Regulation of the complex pattern of sevenless expression in the developing Drosophila eye.

Inducible cell ablation in Drosophila by cold-sensitive ricin A chain

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