Acetylated microtubules are required for maintenance of the barrier between two adjacent tissues

Microtubule acetylation is found in populations of stable, long-lived microtubules, occurring on the conserved lysine 40 (K40) residue of α-tubulin, catalyzed by α-tubulin acetyltransferases (αTATs). K40 acetylation has been shown to stabilize microtubules via enhancing microtubule resilience against mechanical stress. Here we show that Drosophila CG17003/leaky (Lky), an αTAT, is required for proper oogenesis. We found that loss of lky disrupted the cell junction between germline cyst and follicle epithelial cells, adjacent cells that form an egg chamber. This resulted in leakage of germline contents into somatic follicle cells. The follicle cells that received germline-derived nanos gene product failed to maintain their cell fate, leading to an egg chamber fusion. The same phenotype was observed upon replacement of major α-tubulin84B K40 with α-tubulin84B K40A (non-acetylable tubulin), suggesting α-tubulin K40 acetylation is required for the boundary integrity of these two adjacent tissues. Taken together, this study provides the first in vivo function of tubulin acetylation in maintaining the integrity of a tissue barrier.