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.