title: Generation of New Hairless Alleles by Genomic Engineering at the Hairless Locus in Drosophila melanogaster.
abstract: Hairless (H) is the major antagonist within the Notch signalling pathway of Drosophila melanogaster. By binding to Suppressor of Hairless [Su(H)] and two co-repressors, H induces silencing of Notch target genes in the absence of Notch signals. We have applied genomic engineering to create several new H alleles. To this end the endogenous H locus was replaced with an attP site by homologous recombination, serving as a landing platform for subsequent site directed integration of different H constructs. This way we generated a complete H knock out allele HattP, reintroduced a wild type H genomic and a cDNA-construct (Hgwt, Hcwt) as well as two constructs encoding H proteins defective of Su(H) binding (HLD, HiD). Phenotypes regarding viability, bristle and wing development were recorded, and the expression of Notch target genes wingless and cut was analysed in mutant wing discs or in mutant cell clones. Moreover, genetic interactions with Notch (N5419) and Delta (DlB2) mutants were addressed. Overall, phenotypes were largely as expected: both HLD and HiD were similar to the HattP null allele, indicating that most of H activity requires the binding of Su(H). Both rescue constructs Hgwt and Hcwt were homozygous viable without phenotype. Unexpectedly, the hemizygous condition uncovered that they were not identical to the wild type allele: notably Hcwt showed a markedly reduced activity, suggesting the presence of as yet unidentified regulatory or stabilizing elements in untranslated regions of the H gene. Interestingly, Hgwt homozygous cells expressed higher levels of H protein, perhaps unravelling gene-by-environment interactions.
authors.affiliation: Universität Hohenheim, Institut für Genetik (240), Garbenstr. 30, 70599, Stuttgart, Germany.
authors.forename: Heiko
authors.initials: H
authors.lastname: Praxenthaler
authors.affiliation: Universität Hohenheim, Institut für Genetik (240), Garbenstr. 30, 70599, Stuttgart, Germany.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Smylla
authors.affiliation: Universität Hohenheim, Institut für Genetik (240), Garbenstr. 30, 70599, Stuttgart, Germany.
authors.forename: Anja C
authors.initials: AC
authors.lastname: Nagel
authors.affiliation: Universität Hohenheim, Institut für Genetik (240), Garbenstr. 30, 70599, Stuttgart, Germany.
authors.forename: Anette
authors.initials: A
authors.lastname: Preiss
authors.affiliation: Universität Hohenheim, Institut für Genetik (240), Garbenstr. 30, 70599, Stuttgart, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Maier
mesh_terms: D000483:Alleles; D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics*; D015870:Gene Expression; D056726:Genetic Association Studies; D005818:Genetic Engineering; D056426:Genetic Loci; D010641:Phenotype; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014921:Wings, Animal / Q000033:anatomy & histology
chemical_list: D029721:Drosophila Proteins; D014157:Transcription Factors; C076560:H protein, Drosophila