Localization and possible functions of Drosophila septins.
The septins are a family of homologous proteins that were originally identified in Saccharomyces cerevisiae, where they are associated with the "neck filaments" and are involved in cytokinesis and other aspects of the organization of the cell surface. We report here the identification of Sep1, a Drosophila melanogaster septin, based on its homology to the yeast septins. The predicted Sep1 amino acid sequence is 35-42% identical to the known S. cerevisiae septins; 52% identical to Pnut, a second D. melanogaster septin; and 53-73% identical to the known mammalian septins. Sep1-specific antibodies have been used to characterize its expression and localization. The protein is concentrated at the leading edge of the cleavage furrows of dividing cells and cellularizing embryos, suggesting a role in furrow formation. Other aspects of Sep1 localization suggest roles not directly related to cytokinesis. For example, Sep1 exhibits orderly, cell-cycle-coordinated rearrangements within the cortex of syncytial blastoderm embryos and in the cells of post-gastrulation embryos; Sep1 is also concentrated at the leading edge of the epithelium during dorsal closure in the embryo, in the neurons of the embryonic nervous system, and at the baso-lateral surfaces of ovarian follicle cells. The distribution of Sep1 typically overlaps, but is distinct from, that of actin. Both immunolocalization and biochemical experiments show that Sep1 is intimately associated with Pnut, suggesting that the Drosophila septins, like those in yeast, function as part of a complex.
Fares
H
H
Department of Biology, University of North Carolina, Chapel Hill 27599, USA.
Peifer
M
M
Pringle
J R
JR
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002465:Cell Movement; D017931:DNA Primers; D003851:Deoxyribonucleases / Q000032:analysis / Q000096:biosynthesis / Q000502:physiology*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000502:physiology; D005095:Exoribonucleases; D005260:Female; D005455:Fluorescent Antibody Technique; D005656:Fungal Proteins / Q000032:analysis / Q000096:biosynthesis / Q000502:physiology*; D008840:Microfilament Proteins; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010053:Ovary / Q000166:cytology / Q000502:physiology; D014176:Protein Biosynthesis; D011506:Proteins / Q000032:analysis / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D012469:Salivary Glands / Q000166:cytology / Q000502:physiology; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D029721:Drosophila Proteins; D005656:Fungal Proteins; D008840:Microfilament Proteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; C087195:pnut protein, Drosophila; D003851:Deoxyribonucleases; D005095:Exoribonucleases; C068398:XRN1 protein, S cerevisiae