Roles of theDrosophilaNudE protein in kinetochore function and centrosome migration

Abstract

We examined the distribution of the dynein-associated protein NudE in Drosophila larval brain neuroblasts and spermatocytes, and analyzed the phenotypic consequences of a nudE null mutation. NudE can associate with kinetochores, spindles and the nuclear envelope. In nudE mutant brain mitotic cells, centrosomes are often detached from the poles. Moreover, the centrosomes of mutant primary spermatocytes do not migrate from the cell cortex to the nuclear envelope, establishing a new role for NudE. In mutant neuroblasts, chromosomes fail to congress to a tight metaphase plate, and cell division arrests because of spindle assembly checkpoint (SAC) activation. The targeting of NudE to mitotic kinetochores requires the dyneininteracting protein Lis1, and surprisingly Cenp-meta, a Drosophila CENP-E homolog. NudE is non-essential for the targeting of all mitotic kinetochore components tested. However, in the absence of NudE, the 'shedding' of proteins off the kinetochore is abrogated and the SAC cannot be turned off, implying that NudE regulates dynein function at the kinetochore. Supplementary material available online at

TheDrosophilaRZZ complex: roles in membrane traffic and cytokinesis

“…We have shown that in dividing spermatocytes Zw10, Rod and Zwilch all accumulate at the spindle envelope midzone (SEMZ); a similar enrichment at the SEMZ was previously observed for Mast/Orbit, Cenp-Meta and NudE (Inoue et al, 2004;Wainman et al, 2009). However, when the RZZ complex fails to form, none of its components accumulate at the SEMZ.…”

“…We thus examined spermatid morphology in zw10, rod and zwilch mutants. We also analyzed mutants in nudE and cenp-meta (cmet; one of the two homologues of mammalian CENPE), because the protein products of both genes physically interact with Zw10, are involved in the SAC machinery, and accumulate at the SEMZ (Williams et al, 2003;Wainman et al, 2009). The analysis of live spermatids from testis squashes of third instar larvae confirmed the presence of multinucleated spermatids with a single large nebenkern in zw10 mutants, but did not reveal similar cytokinesis defects in rod, zwilch, cmet or nudE mutants (Table 1).…”

“…The localization of Zw10 at the SEMZ can therefore not be essential for cytokinesis, because zwilch and rod mutants lacking the Zw10 band at the SEMZ are not cytokinesis defective. Although Zw10, Rod, Zwilch, Mast/Orbit, CenpMeta and NudE have different functions in cell division (Inoue et al, 2004;Karess, 2005;Wainman et al, 2009), they share the property of being enriched at both the kinetochores and the SEMZ. This fact raises the possibility that most Drosophila proteins that accumulate at the kinetochore, but are not integral components of this structure, move to the SEMZ and concentrate there during spermatocyte ana-telophase.…”

Regulation of dynein localization and centrosome positioning by Lis-1 and asunder during Drosophila spermatogenesis

“…The phenotype of persistent cortical centrosomes during meiotic divisions has been characterized in abnormal spindles and nudE testes; Wainman et al also noted the presence of cortical centrosomes in Lis-1 k11702 metaphase spermatocytes in their study of nudE mutants (Rebollo et al, 2004;Wainman et al, 2009). Dynein-dynactin and LIS-1 localize to the cell periphery in lower eukaryotes and cultured mammalian cells, as well as to the posterior cortex of Drosophila oocytes (Busson et al, 1998;Dujardin and Vallee, 2002;Faulkner et al, 2000).…”

“…Axonemal dynein promotes microtubule sliding for beating of cilia and flagella. Cytoplasmic dynein moves processively along microtubules and, in addition to organelle positioning and transport, plays key roles in cell cycle events, including nucleus-centrosome coupling, nuclear envelope breakdown, spindle assembly/positioning and chromosome segregation (Gusnowski and Srayko, 2011;Hebbar et al, 2008;Huang et al, 2011;Salina et al, 2002;Splinter et al, 2010;Stuchell-Brereton et al, 2011;Wainman et al, 2009). Dynein is a large complex composed of four subunit types: heavy (containing motor activity), light, intermediate and light intermediate chains (Höök and Vallee, 2006;Susalka and Pfister, 2000).…”