Fungal immunoproteomics can be confounded by multiple antigen nomenclatures. Aspergillus
fumigatus GliG, a GST involved in gliotoxin biosynthesis (Davis et al., 2011), was previously proposed to be a fungal allergen based on in silico analysis (Bowyer & Denning, 2007). These authors named GliG as ‘Asp f GST’. Shankar et al. (2005) demonstrated human antibody reactivity against GSTs from different fungal species, including A. fumigatus, and a recombinant GST from Alternaria alternata was identified as a major fungal allergen (Shankar et al., 2006) (called Alt A GST or Alt A 13 in Bowyer & Denning, 2007). Alt A GST shares 76% identity with Asp f GST (i.e. A. fumigatus GliG; Bruns Cell Cycle inhibitor et al. 2010; Davis et al., 2011). Thus, GliG is the same protein as Asp f GST (Bowyer & Denning, 2007) and exhibits 94.8% sequence similarity to that identified by Shankar et al. (2006). GliG was not identified in mycelial or conidial immunoproteomic investigations as exhibiting antibody reactivity. The absence of previous GliG detection illustrates a potential limitation of global immunoproteomic approaches, whereby differentially, or low-level, expressed – yet antigenic – proteins will not be detected. Schrettl et al. (2010) observed widespread immunoreactivity in human sera against
A. fumigatus GliT and suggested that immunoaffinity purification of antibodies from human, or animal sera, using recombinant fungal antigens could represent a valuable source PLX3397 ic50 of antigen-specific
reagents for native protein identification in the organism. This proposal, which may potentially obviate the requirement for antisera generation, also has applications in other species, which induce generalized immune responses in animals. Proteomics will play a major role Orotic acid in future research into the nature, and biotechnological uses, of fungi. The assignment of biological roles to both in silico annotated, and unannotated genes, remains a significant challenge. Allied to robust analytical strategies such as quantitative proteomics, and RNAseq for the assessment of altered gene expression, the emerging availability of online resources for functional categorization of fungal genes and proteins (Priebe et al., 2011) will contribute considerably to this challenge. It has been suggested that fungal protein identification by protein mass spectrometry is reminiscent of stamp collecting. However, a better analogy may be the completion of a mega jigsaw puzzle and it is only when all the pieces are in place that the true richness and complexity of fungal proteomes will be revealed. Fungal proteomics research in the author’s laboratory is funded by HEA PRTLI, Enterprise Ireland and IRCSET. “
“Over the past 15 years, microbial functional genomics has been made possible by the combined power of genome sequencing and microarray technology.