Evolution and Application of Inteins in Candida species: A Review

Abstract

Inteins are invasive intervening sequences that perform an autocatalytic splicing from their host proteins. Among eukaryotes, these elements are present in many fungal species, including those considered opportunistic or primary pathogens, such as Candida spp. Here we reviewed and updated the list of Candida species containing inteins in the genes VMA, THRRS and GLT1 and pointed out the importance of these elements as molecular markers for molecular epidemiological researches and species-specific diagnosis, since the presence, as well as the size of these inteins, is polymorphic among the different species. Although absent in Candida albicans, these elements are present in different sizes, in some environmental Candida spp. and also in most of the non-albicans Candida spp. considered emergent opportunistic pathogens. Besides, the possible role of these inteins in yeast physiology was also discussed in the light of the recent findings on the importance of these elements as post-translational modulators of gene expression, reinforcing their relevance as alternative therapeutic targets for the treatment of non-albicans Candida infections, because, once the splicing of an intein is inhibited, its host protein, which is usually a housekeeping protein, becomes non-functional.

The dynamic intein landscape of eukaryotes

“…In order to assess insertion site conservation, the PDB structures of these exteins were uploaded to ConSurf [ 52 ], a bioinformatics tool for estimating the evolutionary conservation of amino acid positions in a protein based on the phylogenetic relations between homologous sequences. The ConSurf alignments of nDNA exteins Prp8, VMA1, GLT, and ThrRS reveal they are all in highly conserved sites, as previously noted by several groups [ 14 , 34 , 49 ] (Fig. 4 , yellow highlighting; Additional file 1 : Figure S4).…”

“…Ascomycetes with inteins represent some notable pathogenic Fungi, such as Candida spp. [ 34 ] and Aspergillus spp. [ 12 ].…”

“…It was observed that prokaryotic inteins localize to highly conserved sites of vital proteins [ 14 , 31 , 34 ]. In general, this trend holds true for inteins in eukaryotes and their viruses (Fig.…”

Species-specific detection of Candida tropicalis using evolutionary conserved intein DNA sequences

“…Inteins are one such choice as the sequence is often found in the conserved regions of housekeeping genes (Fernandes et al . ). Intein research has intensified in last decades and use of intein sequences for species‐specific diagnosis is the current focus (Fernandes et al .…”

“…Intein research has intensified in last decades and use of intein sequences for species‐specific diagnosis is the current focus (Fernandes et al . ). This study focuses on intein sequences as the potential biomarkers for specific detection of C. tropicalis .…”