deltex, a locus interacting with the neurogenic genes, Notch, Delta and mastermind in Drosophila melanogaster

• Published in: Genetics (Austin) Vol. 126; no. 3; pp. 665 - 677
• Main Authors: Xu T, Artavanis Tsakonas S
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Genetics Soc America 01.11.1990; Genetics Society of America
• Subjects: Alleles; Animals; Biological and medical sciences; biological development; chromosome; chromosomes; Classical genetics, quantitative genetics, hybrids; cromosomas; desarrollo biologico; desarrollo embrionario; developpement biologique; developpement embryonnaire; drosophila melanogaster; Drosophila melanogaster - embryology; Drosophila melanogaster - genetics; embryonic development; expresion genica; expression des genes; fenotipos; Fundamental and applied biological sciences. Psychology; gene; gene expression; gene interaction; gene recessif; genes; genes recesivos; Genetic Complementation Test; genetica; genetics; Genetics of eukaryotes. Biological and molecular evolution; genetique; interaccion de genes; interaction genique; Invertebrata; Investigations; loci; locus; Membrane Proteins - genetics; mutacion; Mutation; nervous system; Phenotype; phenotypes; recessive genes; Sequence Homology, Nucleic Acid; sex; sexe; sexo; sistema nervioso; Suppression, Genetic; systeme nerveux; Zygote - metabolism; Embryonic development; Phenotype; Gene interaction; Arthropoda; Insecta; Nervous system; Invertebrata; Suppressor gene; Drosophila melanogaster; Diptera; Drosophilidae
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/126.3.665

The Notch locus of Drosophila melanogaster, which codes for a transmembrane protein sharing homology with the mammalian epidermal growth factor, is one of a small number of zygotically acting genes, the so called neurogenic loci, which are necessary for the correct segregation of neural from epidermal lineages during embryogenesis. In an attempt to identify genes whose products may interact with that of Notch, we designed a genetic screen aimed at identifying suppressors of certain Notch mutations which are known to affect the extracellular epidermal growth factor homologous domain of Notch. Mutations in two neurogenic loci were identified as suppressors: Delta, whose product was recently shown to interact with Notch and mastermind. In addition, a third, X-linked gene was shown capable of acting as a suppressor. We show that this gene is the deltex locus, characterize the phenotype of deltex mutations, and demonstrate both a maternal and zygotic action of the locus. All deltex alleles behave as recessive viables affecting wing, ocellar and eye morphology. There are allele specific interactions between deltex and various Notch alleles; for example, deltex mutants with a reduced dosage of wild-type Notch die as pupae. deltex also interacts with Delta and mastermind in a fashion that is formally analogous to its interaction with Notch. These results emphasize the special relationship between Notch, Delta and mastermind suggested by previous work and indicate that deltex is likely to play an important role in the same genetic circuitry within which these three neurogenic loci operate.