Although the skin is one of the main defense barriers of fish to date, very little is known about the immune implications and the properties of the numerous substances present in skin cells. In the present study, terminal carbohydrate composition and some components of the skin immunity (total IgM level, and several enzymatic and bacteriostatic activities) present on aqueous and organic epidermal extracts of European sea bass (Dicentrarchus labrax) were determined. Most of the parameters measured followed a protein concentration dose-response.
View Article and Find Full Text PDFThe mechanism of RNAi is well described in metazoans where it plays a role in diverse cellular functions. However, although different classes of endogenous small RNAs (esRNAs) have been identified in fungi, their biological roles are poorly described due, in part, to the lack of phenotype of mutants affected in the biogenesis of these esRNAs. Argonaute proteins are one of the key components of the RNAi pathways, in which different members of this protein family participate in the biogenesis of a wide repertoire of esRNAs molecules.
View Article and Find Full Text PDFEndogenous short RNAs (esRNAs) play diverse roles in eukaryotes and usually are produced from double-stranded RNA (dsRNA) by Dicer. esRNAs are grouped into different classes based on biogenesis and function but not all classes are present in all three eukaryotic kingdoms. The esRNA register of fungi is poorly described compared to other eukaryotes and it is not clear what esRNA classes are present in this kingdom and whether they regulate the expression of protein coding genes.
View Article and Find Full Text PDFRNA silencing in the zygomycete Mucor circinelloides exhibits uncommon features, such as induction by self-replicative sense transgenes and the accumulation of two size classes of antisense small interfering RNAs (siRNAs). To investigate whether this silencing phenomenon follows the rules of a canonical RNA-silencing mechanism, we used hairpin RNA (hpRNA)-producing constructs as silencing triggers and analyzed the efficiency and stability of silencing in different genetic backgrounds. We show here that the dsRNA-induced silencing mechanism is also associated with the accumulation of two sizes of antisense siRNAs and that this mechanism is not mediated by the previously known dcl-1 (dicer-like) gene, which implies the existence of an additional dicer gene.
View Article and Find Full Text PDFDicer proteins are ribonuclease III enzymes that process double stranded RNA precursors into small RNAs categorized as small interfering RNAs (siRNAs) or microRNAs (miRNAs), which suppress gene expression through the RNA silencing mechanism. We have isolated a dicer-like gene (dcl-1) of Mucor circinelloides, the first gene of this family to be identified in zygomycetes. The dcl-1 mRNA occurred in multiple forms, including the truncated molecules that result from premature polyadenylation.
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