Identification of a novel basal body-localized epsilon-tubulin in Leishmania

Epsilon-tubulins are unconventional isoforms of the tubulin family, found in only a few organisms so far. We identified a novel epsilon-tubulin in Leishmania major (Lme-tubulin) that exhibits significant sequence similarity and conservation of functional domains with its known counterparts. Lme-tubulin was found to be constitutively expressed in both the extracellular promastigote form of the parasite and the amastigotes residing within infected macrophages. For localization studies, we generated a Leishmania strain expressing mNeonGreen-tagged Lme-tubulin using CRISPR-Cas9-mediated endogenous protein tagging method. Imaging studies with this strain revealed Lme-tubulin to be localized near the kinetoplast and at the flagellar base, indicating a basal body localization. That Lme-tubulin is indeed localized at the basal body and not a part of the microtubular network was confirmed when its localization was found to remain unaltered upon treatment with nocodazole, a microtubule disruptor. This is the first experimental finding of an e-tubulin not only in the genus Leishmania but in the entire Trypanosomatidae family and is likely to incite further research to uncover the physiological role of this intriguing tubulin in this group of protozoan parasites. Summary StatementWe report for the first time an epsilon-tubulin in Leishmania parasite. This nocodazole-insensitive unconventional tubulin is expressed constitutively and found to be localized in the basal body.