Unraveling the genetic complexity of Drosophila stardust during photoreceptor morphogenesis and prevention of light-induced degeneration.
Drosophila Stardust, a membrane-associated guanylate kinase (MAGUK), recruits the transmembrane protein Crumbs and the cytoplasmic proteins DPATJ and DLin-7 into an apically localized protein scaffold. This evolutionarily conserved complex is required for epithelial cell polarity in Drosophila embryos and mammalian cells in culture. In addition, mutations in Drosophila crumbs and DPATJ impair morphogenesis of photoreceptor cells (PRCs) and result in light-dependent retinal degeneration. Here we show that stardust is a genetically complex locus. While all alleles tested perturb epithelial cell polarity in the embryo, only a subset of them affects morphogenesis of PRCs or induces light-dependent retinal degeneration. Alleles retaining particular postembryonic functions still express some Stardust protein in pupal and/or adult eyes. The phenotypic complexity is reflected by the expression of distinct splice variants at different developmental stages. All proteins expressed in the retina contain the PSD95, Discs Large, ZO-1 (PDZ), Src homology 3 (SH3), and guanylate kinase (GUK) domain, but lack a large region in the N terminus encoded by one exon. These results suggest that Stardust-based protein scaffolds are dynamic, which is not only mediated by multiple interaction partners, but in addition by various forms of the Stardust protein itself.
Berger
Sandra
S
Max-Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, D-10307 Dresden, Germany.
Bulgakova
Natalia A
NA
Grawe
Ferdi
F
Johnson
Kevin
K
Knust
Elisabeth
E
D000483:Alleles; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development*; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D005260:Female; D015870:Gene Expression; D017344:Genes, Insect; D051528:Guanylate Kinases; D008027:Light / Q000009:adverse effects; D008297:Male; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D009024:Morphogenesis; D009154:Mutation; D009703:Nucleoside-Phosphate Kinase / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D017956:Photoreceptor Cells, Invertebrate / Q000254:growth & development* / Q000528:radiation effects; D017434:Protein Structure, Tertiary; D012162:Retinal Degeneration / Q000235:genetics / Q000517:prevention & control
D017931:DNA Primers; D029721:Drosophila Proteins; D026901:Membrane Transport Proteins; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases; C444479:sdt protein, Drosophila