Tesařová P., Nohynkova E., (2002) A new paraxonemal protein in Giardia intestinalis. Abstract in The Journal of Eukaryotic Microbiology 49 (2): 9 A, no38

ISSN 1066-5234, IF 1,739
ABSTRACT. Paraxonemal structures of different morphological pattern parallel flagellar axonemes in cells of several unrelated groups of protists, including retortamonads, diplomonads, parabasalids, kinetoplastids etc. Of these, a paraflagellar rod (PFR) of trypanosomatids is well characterized while little is known about others. The PFR consists of two major closely related proteins, PFR1 and PFR 2, which together with some minor proteins compose a highly ordered paracrystalline structure alongside the flagellar axoneme. We used two monoclonal antibodies, L13D6 and L8C4, specific for the major paraflagellar proteins of Trypanosoma brucei (PFR-A and PFR-C) to test whether related proteins are present in paraxonemal structures found in Giardia intestinalis, G. muris and Tritrichomonas foetus. In Giardia, different structures accompany ventral flagellar axonemes and intracytoplasmic portions of axonemes of anterolateral and posterolateral flagella, in T.foetus, an undulating membrane associated recurrent flagellum contains a rod-like paracrystalline structure. In indirect immunofluorescence, the antibody L13D6 which recognizes both T.brucei PFR-A and PFR-C decorated specifically intracytoplasmic portions of both axonemes of anterolateral flagellar pair in G.intestinalis. Double-label staining with monoclonal antibody against alpha tubulin showed that the L13D6 antibody label was localized anteriorly to the axonemes in close proximity to axonemal microtubules. During cell division, the paraxonemal label disappeared in prophase in accord with flagellar rearrangement and reappeared in telophase when daughter anterolateral flagella assumed the typical interphase arrangement. Surprisingly, no label was detected in any phase of G.muris or T.foetus cell cycles. The antibody L8C4, specific for the PFR-A only, did not recognize any epitope in any of the flagellates tested.