Tubulin-binding cofactor E-like (TBCEL), the protein product of the gene, is required in the germline for the regulation of inter-flagellar microtubule dynamics during spermatid individualization.

Individual sperm cells are resolved from a syncytium during late step of spermiogenesis known as individualization, which is accomplished by an Individualization Complex (IC) composed of 64 investment cones. encodes Tubulin-binding cofactor E-like (TBCEL), suggesting a role for microtubule dynamics in individualization. Indeed, a population of ∼100 cytoplasmic microtubules fails to disappear in mutant testes during spermatogenesis. This persistence, detected using epi-fluorescence and electron microscopy, suggests that removal of these microtubules by TBCEL is a prerequisite for individualization. Immunofluorescence reveals TBCEL expression in elongated spermatid cysts. In addition, testes from mutant males were rescued to wild type using to drive TBCEL expression, indicating that the mutant phenotype is caused by the lack of TBCEL. Finally, RNAi driven by -GAL4 successfully phenocopied , confirming that is required in the germline for individualization. We propose a model in which the cytoplasmic microtubules serve as alternate tracks for investment cones in mutant testes.This article has an associated First Person interview with the first author of the paper.