Analysis of microtubule cytoskeleton distribution using a fluorescent taxoid in two trichomonadid protozoa: Trichomonas gallinae and Tritrichomonas foetus

Omics Analyses of Trichomonas vaginalis Actin and Tubulin and Their Participation in Intercellular Interactions and Cytokinesis

Actin and tubulin proteins from Trichomonas vaginalis are crucial for morphogenesis and mitosis. This parasite has 10 and 11 genes coding bonafide actin and tubulin proteins, respectively. Hence, the goal of this work was to analyze these actin and tubulin genes, their expression at the mRNA and protein levels, and their parasite localization in intercellular interaction and cytokinesis. Representative bonafide actin (tvact1) and tubulin (tvtubα1) genes were cloned into and expressed in Escherichia coli. The recombinant proteins TvACT1r and TvTUBα1r were affinity purified and used as antigens to produce polyclonal antibodies. These antibodies were used in 1DE and 2DE WB and indirect immunofluorescence assays (IFA). By IFA, actin was detected as a ring on the periphery of ameboid, ovoid, and cold-induced cyst-like parasites, on pseudopods of amoeboid parasites, and in cytoplasmic extensions (filopodia) in cell–cell interactions. Tubulin was detected in the axostyle, flagellum, undulating membrane, and paradesmose during mitosis. Paradesmose was observed by IFA mainly during cytokinesis. By scanning electron microscopy, a tubulin-containing nanotubular structure similar to the tunneling nanotubes (TNTs) was also detected in the last stage of cytokinesis. In conclusion, actin and tubulin are multigene families differentially expressed that play important roles in intercellular interactions and cytokinesis.

Fluorescent taxoid probes for microtubule research

The use of the antitumor drug taxol as an experimental microtubule-stabilizing agent is widespread. Fluorescent taxol conjugates, although less employed, are very useful tools for several purposes in microtubule research. These include easily visualizing microtubule cytoskeletons in a variety of cells as well as in vitro assembled microtubules, studying the molecular recognition processes of taxoids by microtubules and investigating new microtubule-stabilizing agents. This chapter describes both the methods for working with fluorescent taxol conjugates and several applications employing the active fluorescent taxoids Flutax-1, Flutax-2, Hexaflutax, Rotax, and FChitax-3. These methods include visualizing microtubules in native and mildly fixed cytoskeletons from cultured cells, ciliate and flagellate protozoans and in living tumor cells, purification of tubulin from tumor cell lines and measurement of its taxoid binding capacity. The applications discussed include a homogeneous assay to screen for compounds binding the taxol site, the determination of the pathway of taxol entry into microtubules and the design of high affinity microtubule-stabilizing agents.