Correct microtubule organization and function are fundamental to many aspects of cellular development, including oogenesis (the formation of eggs), a process known to require microtubule organizing centers (MTOCs), a component of which is γ-tubulin—a protein known to be involved in microtubule nucleation. In Drosophila, two γ-tubulin genes have been identified: γTub23C, expressed in all tissue and cell types, and γTub37C, expressed only in the ovaries. Individual mutations in these genes exhibit exclusive phenotypes, neither significantly related to oogenesis, suggesting that functional redundancy between the genes was obscuring its involvement. In the August 12 PNAS, Gaia Tavosanis and Cayetano Gonzalez at the European Molecular Biology Laboratory investigated the consequences of depleting both Drosophila γ-tubulins and identified their role in female germ cell differentiation (PNAS, DOI:10.1073/pnas.1731925100, August 12, 2003).

Tavosanis and Gonzalez created flies homozygous for severe mutant alleles of each of the two Drosophila γ-tubulin genes. Female...