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. Author manuscript; available in PMC: 2013 Aug 1.

Published in final edited form as: Mol Microbiol. 2012 Jul 5;85(3):557–573. doi: 10.1111/j.1365-2958.2012.08127.x

A. BRG1 Over-expression attenuates virulence in a wild-type strain. Approximately 4.6×10⁵ (dark lines) or 2.4×10⁵ (light lines) yeast cells of C. albicans strain tet-BRG1 (ICY171) were injected into mice. Survival differences between Plus DOX and No DOX groups at both high and low doses were significantly different (p=0.0016 and p=0.0018, respectively). Examination of kidneys retrieved from mice that succumbed to the infection revealed extensive C. albicans growth (GMS staining, upper panels), and infiltration of numerous neutrophils (H&E staining, lower panels). Interestingly, examination of the kidney retrieved from a mouse that survived the infection (No DOX) revealed a subcapsular scar (H&E staining, far right panel) indicative of earlier tissue damage.

B. For timed sacrifice experiments, approximately 1.7×10⁶ (6 h sacrifice) or 3.9×10⁵ (3 day sacrifice) yeast cells of the tet-BRG1 strain (ICY171) were injected into mice. The indicated tissues were homogenized and plated onto Sabouraud agar to determine the fungal burdens (group median indicated by a bar). There was a significant reduction (p=0.0212) in kidney fungal burdens upon BRG1 over-expression (6 h sacrifice). Examination of kidneys retrieved after 3 days from the BRG1 over-expression group (No DOX) revealed kidney necrosis and significant vascular thrombosis (H&E staining, upper panels) associated with invasive C. albicans growth (GMS staining, lower panel).

C. BRG1 Over-expression results in attenuated virulence in the tet-NRG1 background. Approximately 6.0×10⁵ (dark lines) or 2.4×10⁵ (light lines) yeast cells of the tet-NRG1+tet-BRG1 strain (ICY175) were injected into mice. The dashed line represents the survival data produced by the parental tet-NRG1 strain (SSY50-B) when NRG1 levels are elevated (Saville et al., 2003). Survival differences between the Plus DOX and No DOX groups were not statistically significant at the high dose (p=0.1573) but were at the low dose (p=0.0031). Examination of kidneys retrieved from infected mice revealed extensive lesions containing hyphal cells irrespective of the presence or absence of doxycycline (H&E staining, upper panels; GMS staining, lower panels). This contrasts starkly with the tet-NRG1 strain that grows only as yeast cells in the kidney in the absence of DOX (Saville et al., 2003).

A. BRG1 Over-expression attenuates virulence in a wild-type strain. Approximately 4.6×10⁵ (dark lines) or 2.4×10⁵ (light lines) yeast cells of C. albicans strain tet-BRG1 (ICY171) were injected into mice. Survival differences between Plus DOX and No DOX groups at both high and low doses were significantly different (p=0.0016 and p=0.0018, respectively). Examination of kidneys retrieved from mice that succumbed to the infection revealed extensive C. albicans growth (GMS staining, upper panels), and infiltration of numerous neutrophils (H&E staining, lower panels). Interestingly, examination of the kidney retrieved from a mouse that survived the infection (No DOX) revealed a subcapsular scar (H&E staining, far right panel) indicative of earlier tissue damage.

B. For timed sacrifice experiments, approximately 1.7×10⁶ (6 h sacrifice) or 3.9×10⁵ (3 day sacrifice) yeast cells of the tet-BRG1 strain (ICY171) were injected into mice. The indicated tissues were homogenized and plated onto Sabouraud agar to determine the fungal burdens (group median indicated by a bar). There was a significant reduction (p=0.0212) in kidney fungal burdens upon BRG1 over-expression (6 h sacrifice). Examination of kidneys retrieved after 3 days from the BRG1 over-expression group (No DOX) revealed kidney necrosis and significant vascular thrombosis (H&E staining, upper panels) associated with invasive C. albicans growth (GMS staining, lower panel).

C. BRG1 Over-expression results in attenuated virulence in the tet-NRG1 background. Approximately 6.0×10⁵ (dark lines) or 2.4×10⁵ (light lines) yeast cells of the tet-NRG1+tet-BRG1 strain (ICY175) were injected into mice. The dashed line represents the survival data produced by the parental tet-NRG1 strain (SSY50-B) when NRG1 levels are elevated (Saville et al., 2003). Survival differences between the Plus DOX and No DOX groups were not statistically significant at the high dose (p=0.1573) but were at the low dose (p=0.0031). Examination of kidneys retrieved from infected mice revealed extensive lesions containing hyphal cells irrespective of the presence or absence of doxycycline (H&E staining, upper panels; GMS staining, lower panels). This contrasts starkly with the tet-NRG1 strain that grows only as yeast cells in the kidney in the absence of DOX (Saville et al., 2003).