Mutations in twinstar, a Drosophila gene encoding a cofilin/ADF homologue, result in defects in centrosome migration and cytokinesis.

Citations Over TimeTop 10% of 1995 papers

Abstract

We describe the phenotypic and molecular characterization of twinstar (tsr), an essential gene in Drosophila melanogaster. Two P-element induced alleles of tsr (tsr1 and tsr2) result in late larval or pupal lethality. Cytological examination of actively dividing tissues in these mutants reveals defects in cytokinesis in both mitotic (larval neuroblast) and meiotic (larval testis) cells. In addition, mutant spermatocytes show defects in aster migration and separation during prophase/prometaphase of both meiotic divisions. We have cloned the gene affected by these mutations and shown that it codes for a 17-kD protein in the cofilin/ADF family of small actin severing proteins. A cDNA for this gene has previously been described by Edwards et al. (1994). Northern analysis shows that the tsr gene is expressed throughout development, and that the tsr1 and tsr2 alleles are hypomorphs that accumulate decreased levels of tsr mRNA. These findings prompted us to examine actin behavior during male meiosis to visualize the effects of decreased twinstar protein activity on actin dynamics in vivo. Strikingly, both mutants exhibit abnormal accumulations of F-actin. Large actin aggregates are seen in association with centrosomes in mature primary spermatocytes. Later, during ana/telophase of both meiotic divisions, aberrantly large and misshaped structures appear at the site of contractile ring formation and fail to disassemble at the end of telophase, in contrast with wild-type. We discuss these results in terms of possible roles of the actin-based cytoskeleton in centrosome movement and in cytokinesis.

Related Papers

• → Microtubule-nucleating activity of centrosomes in Chinese hamster ovary cells is independent of the centriole cycle but coupled to the mitotic cycle.(1981)191 cited
• → Centriole and Centrosome Dynamics during the Embryonic Cell Cycles That Follow the Formation of the Cellular Blastoderm inDrosophila(1997)79 cited
• → Relocalization of human chromatin remodeling cofactor TIP48 in mitosis(2005)55 cited
• → Dynamic centriolar localization of Polo and Centrobin in early mitosis primes centrosome asymmetry(2020)27 cited
• → Dynamic centriolar relocalization of Polo kinase and Centrobin in early mitosis primes centrosome asymmetry in fly neural stem cells(2018)