TY - JOUR
T1 - Molecular characterization of two types of rDNA units in a single strain of Candida albicans
AU - Miletti-González, Karl E.
AU - Leibowitz, Michael J
PY - 2008/11
Y1 - 2008/11
N2 - Strains of the opportunistic fungal pathogen Candida albicans vary in the presence or absence of a self-splicing group I intron ribozyme (Ca.LSU) in the 25S rRNA gene on chromosome R. Strains of C. albicans typically either lack or contain this ribozyme. However, some strains have both intron-containing and intronless rRNA genes (rDNA). Pulsed-field gel electrophoresis analysis of undigested and restricted DNA showed at least six different karyotypes among eight independent colonies of such a heteroallelic strain. In each case, the variation was in chromosome R, and was due to changes in the number of rDNA units. In strains with only one type of rDNA, chromosome R also varied considerably. Polymerase chain reaction amplification spanning the rDNA unit demonstrated that intron-containing rDNA units are tandemly arrayed, and are immediately adjacent to intronless units in the same cluster. Both types of units were present in the rDNA clusters of both R chromosomes. Possible explanations of these results are loss of Ca.LSU group I intron through purifying selection and/or a relaxation of the commonly accepted concerted evolution of the rDNA units.
AB - Strains of the opportunistic fungal pathogen Candida albicans vary in the presence or absence of a self-splicing group I intron ribozyme (Ca.LSU) in the 25S rRNA gene on chromosome R. Strains of C. albicans typically either lack or contain this ribozyme. However, some strains have both intron-containing and intronless rRNA genes (rDNA). Pulsed-field gel electrophoresis analysis of undigested and restricted DNA showed at least six different karyotypes among eight independent colonies of such a heteroallelic strain. In each case, the variation was in chromosome R, and was due to changes in the number of rDNA units. In strains with only one type of rDNA, chromosome R also varied considerably. Polymerase chain reaction amplification spanning the rDNA unit demonstrated that intron-containing rDNA units are tandemly arrayed, and are immediately adjacent to intronless units in the same cluster. Both types of units were present in the rDNA clusters of both R chromosomes. Possible explanations of these results are loss of Ca.LSU group I intron through purifying selection and/or a relaxation of the commonly accepted concerted evolution of the rDNA units.
KW - Candida
KW - Chromosome R
KW - Gene organization
KW - Group I intron
UR - http://www.scopus.com/inward/record.url?scp=57749204554&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=57749204554&partnerID=8YFLogxK
U2 - 10.1111/j.1550-7408.2008.00353.x
DO - 10.1111/j.1550-7408.2008.00353.x
M3 - Article
C2 - 19120798
AN - SCOPUS:57749204554
VL - 55
SP - 522
EP - 529
JO - Journal of Protozoology
JF - Journal of Protozoology
SN - 1066-5234
IS - 6
ER -