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White cells facilitate opposite- and same-sex mating of opaque cells in Candida albicans.

Tao L, Cao C, Liang W, Guan G, Zhang Q, Nobile CJ, Huang G - PLoS Genet. (2014)

Bottom Line: Modes of sexual reproduction in eukaryotic organisms are extremely diverse.Deletion of genes encoding the pheromone precursor proteins and inactivation of the pheromone response signaling pathway (Ste2-MAPK-Cph1) impair the promoting role of white cells (MTLa) in the sexual mating of opaque cells.This coordination between the two different cell types may be a trade-off strategy between sexual and asexual lifestyles in C. albicans.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.

ABSTRACT
Modes of sexual reproduction in eukaryotic organisms are extremely diverse. The human fungal pathogen Candida albicans undergoes a phenotypic switch from the white to the opaque phase in order to become mating-competent. In this study, we report that functionally- and morphologically-differentiated white and opaque cells show a coordinated behavior during mating. Although white cells are mating-incompetent, they can produce sexual pheromones when treated with pheromones of the opposite mating type or by physically interacting with opaque cells of the opposite mating type. In a co-culture system, pheromones released by white cells induce opaque cells to form mating projections, and facilitate both opposite- and same-sex mating of opaque cells. Deletion of genes encoding the pheromone precursor proteins and inactivation of the pheromone response signaling pathway (Ste2-MAPK-Cph1) impair the promoting role of white cells (MTLa) in the sexual mating of opaque cells. White and opaque cells communicate via a paracrine pheromone signaling system, creating an environment conducive to sexual mating. This coordination between the two different cell types may be a trade-off strategy between sexual and asexual lifestyles in C. albicans.

No MeSH data available.


Related in: MedlinePlus

MFA1 expression in white a cells.Two reporter strains GH1600 (SZ306MFA1p-GFP) and GH1603 (wor1Δ/ΔMFA1p-GFP), in which GFP gene was under the control of the MFA1 promoter, were used. wh, white; op, opaque. Strains used: GH1600 and GH1603. (A) α-Pheromone induces MFA1 expression in white a cells. Cells were first grown at 25°C for 36 hours to stationary phase and inoculated into fresh Lee's glucose medium (1×107 cells/ml). α-Pheromone peptide was added every two hours to the cultures over an eight-hour period. The final concentration of α-pheromone peptide was 8×10−6 M. Expression of GFP proteins was examined with a fluorescence microscope. Opaque a cells of strain SZ306MFA1p-GFP served as a control. Images of untreated cells are shown in top panels. “−α-ph”, no α-pheromone added (upper panel); “+α-ph”, α-pheromone added (lower panel). BF, bright field. Scale bar, 10 µm. (B) Opaque α cells induce MFA1 expression in white a cells. 4×106 white a cells of each tester strain indicated were mixed with equal number of opaque α cells (GH1349 MTLα/α). The mixtures were spotted onto Lee's glucose medium and incubated at 25°C for 24 h. Expression of GFP proteins in white cells of the tester strains was examined with a fluorescence microscope. Images of single strain cultures (white cells of the tester strains) are shown in the upper panel. Mixed cultures are shown in the lower panel. BF, bright field. Scale bar, 10 µm.
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pgen-1004737-g002: MFA1 expression in white a cells.Two reporter strains GH1600 (SZ306MFA1p-GFP) and GH1603 (wor1Δ/ΔMFA1p-GFP), in which GFP gene was under the control of the MFA1 promoter, were used. wh, white; op, opaque. Strains used: GH1600 and GH1603. (A) α-Pheromone induces MFA1 expression in white a cells. Cells were first grown at 25°C for 36 hours to stationary phase and inoculated into fresh Lee's glucose medium (1×107 cells/ml). α-Pheromone peptide was added every two hours to the cultures over an eight-hour period. The final concentration of α-pheromone peptide was 8×10−6 M. Expression of GFP proteins was examined with a fluorescence microscope. Opaque a cells of strain SZ306MFA1p-GFP served as a control. Images of untreated cells are shown in top panels. “−α-ph”, no α-pheromone added (upper panel); “+α-ph”, α-pheromone added (lower panel). BF, bright field. Scale bar, 10 µm. (B) Opaque α cells induce MFA1 expression in white a cells. 4×106 white a cells of each tester strain indicated were mixed with equal number of opaque α cells (GH1349 MTLα/α). The mixtures were spotted onto Lee's glucose medium and incubated at 25°C for 24 h. Expression of GFP proteins in white cells of the tester strains was examined with a fluorescence microscope. Images of single strain cultures (white cells of the tester strains) are shown in the upper panel. Mixed cultures are shown in the lower panel. BF, bright field. Scale bar, 10 µm.

Mentions: MFα1 is constitutively expressed in opaque α cells examined over a 48-hour growth period (Figure S4) [28]–[30], while MFA1 is poorly expressed in opaque a cells [22]. When treated with α-pheromone, MFA1 is induced in opaque a cells [22]. We hypothesized that MFA1 may also be induced in white a cells upon addition of α-pheromone to the medium or through production by opaque α cells. If true, in a mixed culture of white a cells and opaque α cells, the α cells should form mating projections as a result of exposure to a-pheromone produced by white a cells. To test this hypothesis, two reporter strains (SZ306MFA1p-GFP and wor1Δ/ΔMFA1p-GFP), in which a GFP coding sequence was integrated at the MFA1 locus and controlled by the MFA1 promoter, were constructed. As shown in Figure 2A, α-pheromone clearly induced MFA1 expression in a proportion of white cells of the two reporter strains as indicated by the GFP fluorescence. Opaque cells of the SZ306a-MFA1p-GFP strain treated with α-pheromone served as a positive control. In the mixed cultures of white a cells and opaque α cells (Figure 2B), the expression of GFP in the two reporter strains was also clear. However, the GFP fluorescence was not observed in the single strain cultures. These results indicate that the presence of α-pheromone, either from its addition to the medium or produced by opaque α cells, is able to induce the expression of MFA1 in white a cells.


White cells facilitate opposite- and same-sex mating of opaque cells in Candida albicans.

Tao L, Cao C, Liang W, Guan G, Zhang Q, Nobile CJ, Huang G - PLoS Genet. (2014)

MFA1 expression in white a cells.Two reporter strains GH1600 (SZ306MFA1p-GFP) and GH1603 (wor1Δ/ΔMFA1p-GFP), in which GFP gene was under the control of the MFA1 promoter, were used. wh, white; op, opaque. Strains used: GH1600 and GH1603. (A) α-Pheromone induces MFA1 expression in white a cells. Cells were first grown at 25°C for 36 hours to stationary phase and inoculated into fresh Lee's glucose medium (1×107 cells/ml). α-Pheromone peptide was added every two hours to the cultures over an eight-hour period. The final concentration of α-pheromone peptide was 8×10−6 M. Expression of GFP proteins was examined with a fluorescence microscope. Opaque a cells of strain SZ306MFA1p-GFP served as a control. Images of untreated cells are shown in top panels. “−α-ph”, no α-pheromone added (upper panel); “+α-ph”, α-pheromone added (lower panel). BF, bright field. Scale bar, 10 µm. (B) Opaque α cells induce MFA1 expression in white a cells. 4×106 white a cells of each tester strain indicated were mixed with equal number of opaque α cells (GH1349 MTLα/α). The mixtures were spotted onto Lee's glucose medium and incubated at 25°C for 24 h. Expression of GFP proteins in white cells of the tester strains was examined with a fluorescence microscope. Images of single strain cultures (white cells of the tester strains) are shown in the upper panel. Mixed cultures are shown in the lower panel. BF, bright field. Scale bar, 10 µm.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4199524&req=5

pgen-1004737-g002: MFA1 expression in white a cells.Two reporter strains GH1600 (SZ306MFA1p-GFP) and GH1603 (wor1Δ/ΔMFA1p-GFP), in which GFP gene was under the control of the MFA1 promoter, were used. wh, white; op, opaque. Strains used: GH1600 and GH1603. (A) α-Pheromone induces MFA1 expression in white a cells. Cells were first grown at 25°C for 36 hours to stationary phase and inoculated into fresh Lee's glucose medium (1×107 cells/ml). α-Pheromone peptide was added every two hours to the cultures over an eight-hour period. The final concentration of α-pheromone peptide was 8×10−6 M. Expression of GFP proteins was examined with a fluorescence microscope. Opaque a cells of strain SZ306MFA1p-GFP served as a control. Images of untreated cells are shown in top panels. “−α-ph”, no α-pheromone added (upper panel); “+α-ph”, α-pheromone added (lower panel). BF, bright field. Scale bar, 10 µm. (B) Opaque α cells induce MFA1 expression in white a cells. 4×106 white a cells of each tester strain indicated were mixed with equal number of opaque α cells (GH1349 MTLα/α). The mixtures were spotted onto Lee's glucose medium and incubated at 25°C for 24 h. Expression of GFP proteins in white cells of the tester strains was examined with a fluorescence microscope. Images of single strain cultures (white cells of the tester strains) are shown in the upper panel. Mixed cultures are shown in the lower panel. BF, bright field. Scale bar, 10 µm.
Mentions: MFα1 is constitutively expressed in opaque α cells examined over a 48-hour growth period (Figure S4) [28]–[30], while MFA1 is poorly expressed in opaque a cells [22]. When treated with α-pheromone, MFA1 is induced in opaque a cells [22]. We hypothesized that MFA1 may also be induced in white a cells upon addition of α-pheromone to the medium or through production by opaque α cells. If true, in a mixed culture of white a cells and opaque α cells, the α cells should form mating projections as a result of exposure to a-pheromone produced by white a cells. To test this hypothesis, two reporter strains (SZ306MFA1p-GFP and wor1Δ/ΔMFA1p-GFP), in which a GFP coding sequence was integrated at the MFA1 locus and controlled by the MFA1 promoter, were constructed. As shown in Figure 2A, α-pheromone clearly induced MFA1 expression in a proportion of white cells of the two reporter strains as indicated by the GFP fluorescence. Opaque cells of the SZ306a-MFA1p-GFP strain treated with α-pheromone served as a positive control. In the mixed cultures of white a cells and opaque α cells (Figure 2B), the expression of GFP in the two reporter strains was also clear. However, the GFP fluorescence was not observed in the single strain cultures. These results indicate that the presence of α-pheromone, either from its addition to the medium or produced by opaque α cells, is able to induce the expression of MFA1 in white a cells.

Bottom Line: Modes of sexual reproduction in eukaryotic organisms are extremely diverse.Deletion of genes encoding the pheromone precursor proteins and inactivation of the pheromone response signaling pathway (Ste2-MAPK-Cph1) impair the promoting role of white cells (MTLa) in the sexual mating of opaque cells.This coordination between the two different cell types may be a trade-off strategy between sexual and asexual lifestyles in C. albicans.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.

ABSTRACT
Modes of sexual reproduction in eukaryotic organisms are extremely diverse. The human fungal pathogen Candida albicans undergoes a phenotypic switch from the white to the opaque phase in order to become mating-competent. In this study, we report that functionally- and morphologically-differentiated white and opaque cells show a coordinated behavior during mating. Although white cells are mating-incompetent, they can produce sexual pheromones when treated with pheromones of the opposite mating type or by physically interacting with opaque cells of the opposite mating type. In a co-culture system, pheromones released by white cells induce opaque cells to form mating projections, and facilitate both opposite- and same-sex mating of opaque cells. Deletion of genes encoding the pheromone precursor proteins and inactivation of the pheromone response signaling pathway (Ste2-MAPK-Cph1) impair the promoting role of white cells (MTLa) in the sexual mating of opaque cells. White and opaque cells communicate via a paracrine pheromone signaling system, creating an environment conducive to sexual mating. This coordination between the two different cell types may be a trade-off strategy between sexual and asexual lifestyles in C. albicans.

No MeSH data available.


Related in: MedlinePlus