Assignment of cloned genes to the seven electrophoretically separated Candida albicans chromosomes.

Abstract

By using orthogonal-field alternating gel electrophoresis (OFAGE), field-inversion gel electrophoresis (FIGE), and contour-clamped homogeneous field gel electrophoresis (CHEF), we have clearly resolved 11 chromosomal bands from various Candida albicans strains. OFAGE resolves the smaller chromosomes better, while FIGE, which under our conditions causes the chromosomes to run in the reverse order of OFAGE, is more effective in separating the larger chromosomes. CHEF separates all chromosomes under some conditions, but these conditions do not often resolve homologs. The strains examined are highly polymorphic for chromosome size. Fourteen cloned Candida genes, isolated on the basis of conferral of new properties to or complementation of auxotrophic deficiencies in Saccharomyces cerevisiae, and three sequences of unknown function have been hybridized to Southern transfers of CHEF, FIGE, and OFAGE gels. Four sets of resolvable bands have been shown to be homologous chromosomes. On the basis of these data, we suggest that C. albicans has seven chromosomes. Genes have been assigned to the seven chromosomes. Two chromosomes identified genetically have been located on the electrophoretic karyotype.

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

“…Thus comparison between the two genomes is possible. The karyotype of C. albicans, determined using pulsefield electrophoresis and Southern blotting, demonstrated that there were 8 chromosomes (Magee, Koltin et al 1988;Lasker, Carle et al 1989;Wickes, Staudinger et al 1991). A major tool in the further characterization of chromosome substructure was the use of the 8-base-pairspecific restriction enzyme SfiI, which cleaves the various chromosomes into from 2 to 8 fragments, ranging in size from 90 to >2200 kb.…”

Telomeric and dispersed repeat sequences in Candida yeasts and their use in strain identification

“…Because C. albicans and related species lack sexual cycles (46), genetic studies have been difficult. Analyses of mitotic recombination of auxotrophic markers (47, 48), DNA content (32, 42), and complexity (32) and chromosome organization by orthogonal field alternating gel electrophoresis (21) indicate that C. albicans possesses a diploid genome organized into about eight chromosome pairs (16,20), with a DNA content and complexity similar to those of bakers' yeast, Saccharomyces cerevisiae (17).The lack of a sexual phase in C. albicans and related species presumably prevents opportunities for recombination between strains, leading to a direct clonal relationship in the descendants. This characteristic may be useful in clinical analyses of colonization and epidemiological studies, since it allows direct determination of strain relatedness by employing genomic markers.…”

Karyotyping of Fluconazole-Resistant Yeasts with Phenotype Reported as Candida krusei or Candida inconspicua

“…Cundidu ulbicans SGY 126 was used as the reference strain to determine the molecular sizes of the chromosome bands in PFGE gels (17,18).…”

“…Recent advances in molecular biology include the application of pulsed-field gel electrophoresis (PFGE) to the taxonomy of yeasts (3, 7,10,11,[16][17][18][19][20]24,26,30). Contour-clamped homogeneous electric field (CHEF) electrophoresis is a variant of this technique which improves chromosomal resolution (9).…”