pThe surface of the protozoan iTrypanosoma cruzi/i is covered by a dense coat of mucin-type glycoconjugates, which make a pivotal contribution to parasite protection and host immune evasion. Their importance is further underscored by the presence of &1000 mucin-like genes in the parasite genome. In the present study we demonstrate that one such group of genes, termed iTcSMUG L/i, codes for previously unrecognized mucin-type glycoconjugates anchored to and secreted from the surface of insect-dwelling epimastigotes. These features are supported by the iin vivo/i tracing and characterization of endogenous TcSMUG L products and recombinant tagged molecules expressed by transfected parasites. Besides displaying substantial homology to TcSMUG S products, which provide the scaffold for the major Gp35/50 mucins also present in insect-dwelling stages of the iT. cruzi/i lifecycle, TcSMUG L products display unique structural and functional features, including being completely refractory to sialylation by parasite itrans/i-sialidases. Although quantitative real time-PCR and gene sequencing analyses indicate a high degree of genomic conservation across the iT. cruzi/i species, TcSMUG L product expression and processing is quite variable among different parasite isolates./p
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