PECULIARITIES OF PROTEIN GLYCOSYLATION IN THE SPORES OF THE MICROSPORIDIA PARANOSEMA (ANTONOSPORA) GRYLLI
V. V. Dolgikh,1 P. B. Semenov,1 G. V. Beznusenko 2
1 All-Russian Institute for Plant Protection, St. Petersburg-Pushkin, Russia,
and 2 Istituto di Ricerche Farmacologiche "Mario Negri", Santa Maria Imbaro (Chieti), Italy;
1 e-mail: dollslav@yahoo.com
Long adaptation of microsporidia, a large group of fungi-related protozoa, to intracellular lifestyle has resulted
in drastic minimization of a parasite cell. Thus, diversity of carbohydrates in microsporidia glycoproteins and
proteoglycans is expected to be restricted by O-linked manno-oligosaccharides because three genes involved in
O-mannosylation of proteins and no components of N-linked glycosylation machinery were found in genome of human
pathogen Encephalitozoon cuniculi. In this study we investigated glycosylation of spore proteins of
microsporidia Paranosema (Antonospora) grylli infecting crickets Gryllus bimaculatus. Using periodic acid-Shiff
reagent staining we have demonstrated that some P. grylli spore proteins are highly-glycosylated. The major
polar tube protein (PTP1) of 56 kDa was shown as the most intensively decorated band. The experiments with
N-glycosidase F and WGA lectin did not reveal any N-glycosylated proteins in P. grylli spores. At the same
time, incubation of major spore wall protein of 40 kDa (p40) with mannose specific lectin GNA resulted in specific
binding that was reduced by pretreatment of the protein with mannosidases. Interestingly, in spite of PTP1
glycosylation, polar tube proteins extracted from P. grylli spores were not precipitated by GNA-agarose. Since
P. grylli and E. cuniculi are distantly related, our data suggest that dramatic reduction of protein
glycosylation machinery is a common feature of microsporidia.
Key words: microsporidia, spores, protein glycosylation, glycoproteins
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