Extensive chromosome rearrangements distinguish the karyotype of the hypovirulent species Candida dubliniensis from the virulent Candida albicans

Abstract

Candida dubliniensis and Candida albicans, the most common human fungal pathogen, have most of the same genes and high sequence similarity, but C. dubliniensis is less virulent. C. albicans causes both mucosal and hematogenously disseminated disease, C. dubliniensis mostly mucosal infections. Pulse-field electrophoresis, genomic restriction enzyme digests, Southern blotting, and the emerging sequence from the Wellcome Trust Sanger Institute were used to determine the karyotype of C. dubliniensis type strain CD36. Three chromosomes have two intact homologues. A translocation in the rDNA repeat on chromosome R exchanges telomere-proximal regions of R and chromosome 5. Translocations involving the remaining chromosomes occur at the Major Repeat Sequence. CD36 lacks an MRS on chromosome R but has one on 3. Of six other C. dubliniensis strains, no two had the same electrophoretic karyotype. Despite extensive chromosome rearrangements, karyotypic differences between C. dubliniensis and C. albicans are unlikely to affect gene expression. Karyotypic instability may account for the diminished pathogenicity of C. dubliniensis.

Efficient neocentromere formation is suppressed by gene conversion to maintain centromere function at native physical chromosomal loci in Candida albicans

“…Like C. albicans, the CdCEN7-deleted chromosome remains mitotically stable in each case (URA3 loss <1 in 10 3 cells) ( Table 1). Of the six C. dubliniensis strains analyzed, no two showed identical karyotypes in a previous study (Magee et al 2008). Thus, it is possible that CdCEN7-deleted chromosomes might have been fused to a natural centric chromosome rather than forming a neocentromere to become mitotically stable as frequently found in fission yeast (Ishii et al 2008).…”

“…Centromere DNA sequences of C. albicans and C. dubliniensis share no sequence homology due to rapid evolution of centromere DNA sequences (Padmanabhan et al 2008), although synteny of genes across CENPA-binding regions in most of the chromosomes is largely maintained in these two species. An SfiI macrorestriction map is now available for both C. albicans (1006 and white opaque switching strain WO-1; Chu et al 1993) and C. dubliniensis (Strain Cd36; Magee et al 2008). C. albicans WO-1 (http://www.broadinstitute.…”

“…The gels were run in 0.53 TBE buffer and maintained at 14°C throughout the procedure. Electrophoresis settings were as follows (Magee et al 2008):…”

High-Frequency Genetic Contents Variations in Clinical Candida albicans Isolates

“…[6][7][8][9][10][11][12][13][14][15] Recently, array technology opened a new dimension in the study of genome instability. Array comparative genomic hybridization (array CGH) allows the detection of genomic variations across a whole genome.…”

“…The instability of the chromosome copy number of entire chromosomes, as well as the large portions of chromosomes was extensively studied with laboratory and freshly isolated strains using pulse-field gene electrophoresis (PFGE) as reviewed by Rustchenko, 3) Rustchenko and Sherman, 4) and Selmecki et al 5) Combined with Southern blot analysis, PFGE allowed limited analysis of gene copy number, and also could be extended to the analysis of chromosome deletions and other rearrangements. [6][7][8][9][10][11][12][13][14][15] Recently, array technology opened a new dimension in the study of genome instability. Array comparative genomic hybridization (array CGH) allows the detection of genomic variations across a whole genome.…”