[Analysis of expression of vesicular transport genes in avesicular cells of the microsporidium Paranosema (Antonospora) locustae].

Long adaptation of microsporidia, a large group fungi-related protozoa, to intracellular lifestyle has resulted in a drastic minimization of parasite cell. Ultrastructural analysis has shown that the Golgi complex of the microsporidia Paranosema (Antonospora) grylli and P. locustae appears as branching or varicose networks of thin tubules. These tubular networks are connected to endoplasmic reticulum, plasma membrane and forming polar tube but have no vesicles. Vesicles were not found even if ultra-fast cryofixation and membrane fusion/uncoating inhibition were used. However, a limited number of genes involved in vesicular transport were found in microsporidia genomes. In this study we used RT-PCR to analyze the content of mRNA transcripts encoding beta and beta' subunits COPI coatomer complex, Sec13 and Sec31 subunits COPII, SNARE-proteins synaptobrevin and syntaxin-like member of SFT family in P. locustae intracellular stages. The level of expression of studied genes was comparable with that of gene encoding alternative oxidase, enzyme envolved in microsporidia core metabolism. Moreover, polyclonal antibodies raised against recombinant Sec13 subunit COPII, expressed in B Escherichia coli, has shown accumulation of the protein is spores and stages of intracellular development as well as its association with membranes. The presence of components of vesicular transport machinery in avesicular microsporidia cells requires their functional analysis.