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Molecular cloning of a second phospholipase B gene, caPLB2 from Candida albicans
Y Sugiyama1, S Nakashima, F Mirbod
1Department of Dermatology, Gifu University School of Medicine, Japan.
Abstract:
Accumulating evidence suggests that phospholipase B, secreted by pathogenic fungi such as Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus, functions as one of the virulence factors. In the present study, we have attempted to clone phospholipase B gene from C. albicans. By RT-PCR analysis with degenerate primers based on conserved regions of phospholipase B from Saccharomyces cerevisiae, Penicillium notatum and Torulaspora delbrueckii two similar but different cDNA fragments were obtained. One corresponded to the partial sequence of caPLB1, recently cloned phospholipase B gene from C. albicans by a different approach (Leidich et al.: J Biol Chem 1998; 273: 26078-86). The other fragments contained sequences similar to the corresponding sequences of phospholipase B from other fungi. The presence of two related genes was confirmed by Southern and Northern blot analyses. The full length of the second C. albicans phospholipase B gene (caPLB2) encoded a putative protein with 608 amino acids and contained a potential signal peptide sequence and a putative catalytic region, which are found in phospholipase B from other fungi. Consistent with the findings of caPLB1, caPLB2 also lacks a cluster of hydrophobic amino acids at the COOH-terminal, which may function as a signal of glycosylphosphatidylinositol anchor.
Insights
Researchers identified a second phospholipase B gene (caPLB2) in Candida albicans, a pathogenic fungus. This gene encodes a protein similar to other fungal phospholipases B, suggesting its role in fungal virulence.
Area of Science:
- Mycology
- Molecular Biology
- Biochemistry
Background:
- Phospholipase B (PLB) is secreted by pathogenic fungi like Candida albicans.
- PLB is recognized as a significant virulence factor in fungal infections.
Purpose of the Study:
- To clone and characterize phospholipase B genes from Candida albicans.
- To investigate the presence and nature of additional PLB genes beyond the previously identified caPLB1.
Main Methods:
- RT-PCR with degenerate primers based on conserved PLB regions.
- Southern and Northern blot analyses to confirm gene presence and expression.
- Sequence analysis of cloned cDNA fragments.
Main Results:
- Two distinct cDNA fragments encoding proteins similar to phospholipase B were obtained.
- One fragment matched the known caPLB1 gene; the second represented a novel gene, caPLB2.
- caPLB2 encodes a putative 608-amino acid protein with a signal peptide and catalytic region, lacking a GPI anchor signal.
Conclusions:
- Candida albicans possesses at least two distinct phospholipase B genes, caPLB1 and caPLB2.
- The newly identified caPLB2 gene likely contributes to fungal virulence, similar to caPLB1.
- The structural features of caPLB2 suggest its role in fungal pathogenesis.