TY - JOUR
T1 - CO2 Regulates White-to-Opaque Switching in Candida albicans
AU - Huang, Guanghua
AU - Srikantha, Thyagarajan
AU - Sahni, Nidhi
AU - Yi, Song
AU - Soll, David R.
N1 - Funding Information:
The authors are indebted to Joachim Morschhäuser at the University of Würzburg, Germany, Alexander Johnson at the University of California, San Francisco, and Gerald R. Fink at Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology for the generous gifts of plasmids and strains. The authors are also indebted to Karla Daniels for help in assembling the figures and Claude Pujol for comments in the manuscript. This research was supported by NIH grant AI2392 and the Developmental Studies Hybridoma Bank-Microbe at Iowa.
PY - 2009/2/24
Y1 - 2009/2/24
N2 - To mate, Candida albicans must undergo homozygosis at the mating type-like locus MTL [1, 2], then switch from the white to opaque phenotype [3, 4]. Paradoxically, when opaque cells are transferred in vitro to 37°C, the temperature of their animal host, they switch en masse to white [5-7], suggesting that their major niche might not be conducive to mating. It has been suggested that pheromones secreted by opaque cells of opposite mating type [8] or the hypoxic condition of host niches [9, 10] stabilize opaque cells. There is, however, an additional possibility, namely that CO2, which achieves levels in the host 100 times higher than in air [11-13], stabilizes the opaque phenotype. CO2 has been demonstrated to regulate the bud-hypha transition in C. albicans [14, 15], expression of virulence genes in bacteria [16], and mating events in Cryptococcus neoformans [14, 17]. We tested the possibility that CO2 stabilizes the opaque phenotype, and found that physiological levels of CO2 induce white-to-opaque switching and stabilize the opaque phenotype at 37°C. It exerts this control equally under anaerobic and aerobic conditions. These results suggest that the high levels of CO2 in the host induce and stabilize the opaque phenotype, thus facilitating mating.
AB - To mate, Candida albicans must undergo homozygosis at the mating type-like locus MTL [1, 2], then switch from the white to opaque phenotype [3, 4]. Paradoxically, when opaque cells are transferred in vitro to 37°C, the temperature of their animal host, they switch en masse to white [5-7], suggesting that their major niche might not be conducive to mating. It has been suggested that pheromones secreted by opaque cells of opposite mating type [8] or the hypoxic condition of host niches [9, 10] stabilize opaque cells. There is, however, an additional possibility, namely that CO2, which achieves levels in the host 100 times higher than in air [11-13], stabilizes the opaque phenotype. CO2 has been demonstrated to regulate the bud-hypha transition in C. albicans [14, 15], expression of virulence genes in bacteria [16], and mating events in Cryptococcus neoformans [14, 17]. We tested the possibility that CO2 stabilizes the opaque phenotype, and found that physiological levels of CO2 induce white-to-opaque switching and stabilize the opaque phenotype at 37°C. It exerts this control equally under anaerobic and aerobic conditions. These results suggest that the high levels of CO2 in the host induce and stabilize the opaque phenotype, thus facilitating mating.
KW - MICROBIO
UR - http://www.scopus.com/inward/record.url?scp=60349128912&partnerID=8YFLogxK
U2 - 10.1016/j.cub.2009.01.018
DO - 10.1016/j.cub.2009.01.018
M3 - Article
C2 - 19200725
AN - SCOPUS:60349128912
SN - 0960-9822
VL - 19
SP - 330
EP - 334
JO - Current Biology
JF - Current Biology
IS - 4
ER -