Fig. 8.

Overexpression of Rab1 rescues cytokinesis failures and neuromotor defects associated with loss of Cog7. (A) Rescue of Cog7 cytokinesis defects by overexpression of Rab1 (Act5C>YFP-Rab1, Cog7^z4495/Cog7^z5797). Testes from 3-day-old males of the indicated genotypes were viewed using phase-contrast microscopy. Cog7^z4495/Cog7^z5797 display irregular spermatids containing multiple nuclei (phase light, arrowhead) associated with enlarged mitochondrial derivatives (phase dark, arrow). Spermatids from Act5C>YFP-Rab1, Cog7^z4495/Cog7^z5797 males display a single nucleus (arrowhead) associated with a mitochondrial derivative (arrow) of similar size. Scale bar: 10 µm. The graph shows the percentage of multinucleate spermatids in the indicated genotypes. Overexpression of Rab1 can suppress the cytokinesis defects associated with Cog7 mutation, as indicated by the significant decrease in multinucleate spermatids. (B) Quantification of adult negative geotaxis as percentage of animals climbing to 2-cm height at 10 s, for Cog7^z4495/Cog7^z5797 and Act5C>YFP-Rab1, Cog7^z4495/Cog7^z5797 animals aged 7 days; n=60 flies for each genotype. (C) Quantification of TS-paralysis phenotype in flies of the indicated genotypes. 100 flies for each genotype were assayed at 38°C for 15 min. Error bars represent s.e.m. *P<0.05; **P<0.01; ***P<0.0001 (unpaired Student's t-test).