Glutamylation, the covalent attachment of glutamic acid to tubulin in the polymerized microtubule, is enriched on long-lived microtubules, and is proposed to contribute to centriole stability, cilia motility and axon function. Glutamylation of the microtubules is catalysed by a family of tubulin tyrosine ligase like (TTLL) enzymes. Comprehensive in vivo analyses of the function of tubulin glutamylation have proved challenging because of the existence of a large family of TTLL enzymes in many species. To investigate the function of tubulin glutamylation we have generated a ttll-4(tm3310); ttll-11(tm4059); ttll-15(tm3871) ttll-5(tm3360) ttll-9(tm3889) quint mutant that lacks all five C. elegans glutamylating TTLL enzymes. The quint mutant shows normal embryonic viability and brood size indicating that the centrioles are functional and the microtubules of the spindle are competent for cell division. Recent evidence suggests that in human cells glutamylation modulates microtubule severing by spastin and katanin. To investigating whether a similar regulatory mechanism also exists in worms we have combined our quint mutant with mei-1(GOF) and mei-1(LOF) alleles of katanin. We do not however observe any suppression of the mei-1-associated lethality when microtubule glutamylation is lost. Our data therefore suggest that, contrary to expectations, microtubule glutamylation is not essential for C. elegans viability, although we do observe a male mating defect indicative of ciliary dysfunction. We are currently undertaking a detailed analysis of microtubule dynamics to determine whether minor perturbations of microtubule function occur in the absence of glutamylation.