Drosophila non-muscle α-actinin is localized in nurse cell actin bundles and ring canals, but is not required for fertility

• Published in: Mechanisms of development 2004-11, Vol.121 (11), p.1377-1391
• Main Authors: Wahlström, Gudrun, Lahti, Vesa-Pekka, Pispa, Johanna, Roos, Christophe, Heino, Tapio I.
• Format: Article
• Language: English
• Subjects: Actin bundles; Actin Cytoskeleton - chemistry; Actinin - analysis; Actinin - genetics; Actinin - physiology; Actins - immunology; Actins - metabolism; Alleles; Alternative Splicing - genetics; Animals; Drosophila - embryology; Embryo, Nonmammalian - cytology; Female; Fertility - genetics; Fertility - physiology; Muscles - metabolism; Mutation - genetics; Nurse cells; Oogenesis; Ovary - chemistry; Ovary - cytology; Protein Isoforms - analysis; Protein Isoforms - genetics; Protein Isoforms - physiology; Ring canals; ultraspiracle; α-Actinin mutant
• ISSN: 0925-4773; 1872-6356
• DOI: 10.1016/j.mod.2004.06.004

The single copy Drosophila α-actinin gene is alternatively spliced to generate three different isoforms that are expressed in larval muscle, adult muscle and non-muscle cells, respectively. We have generated novel α-actinin alleles, which specifically remove the non-muscle isoform. Homozygous mutant flies are viable and fertile with no obvious defects. Using a monoclonal antibody that recognizes all three splice variants, we compared α-actinin distribution in wild type and mutant embryos and ovaries. We found that non-muscle α-actinin was present in young embryos and in the embryonic central nervous system. In ovaries, non-muscle α-actinin was localized in the nurse cell subcortical cytoskeleton, cytoplasmic actin cables and ring canals. In the mutant, α-actinin expression remained in muscle tissues, but also in a subpopulation of epithelial cells in both embryos and ovaries. This suggests that various populations of non-muscle cells regulate α-actinin expression in different ways. We also show that ectopically expressed adult muscle-specific α-actinin localizes to all F-actin containing structures in the nurse cells in the absence of endogenous non-muscle α-actinin.