Figure 7. The ROB1^946S allele appears to be a gain-of-function allele during in vitro filamentation and biofilm formation.

A. A poorly filamenting clinical isolate of C. albicans that is homozygous for the ROB1^946P allele was converted to an SC5314-like ROB1 heterozygote by knock-in of the ROB1^946S allele. The resulting strain shows increased filamentation relative to a strain with knock-in of the exogenous allele on solid Spider medium and RPMI (A) and after induction in liquid RPMI+1%BCS for 4 hr at 37°C (B). The asterisk indicates that the indicated strain differs from SN250 in a statistically significant manner by Student’s t test (P < 0.05). C. SN250 was transformed with knock-in constructs to generate either ROB1 homozygotes or a heterozygote containing NAT markers in the 3’ untranslated region. These filamentation of these strains were compared to the unmarked SN250 heterozygote on Spider medium at 37°C (C) and in liquid RPMI+10% BCS (D). The asterisk indicates that the indicated strain differs from SN250 in a statistically significant manner by Student’s t test corrected for multiple comparisons (P < 0.05). E. The biofilm properties of the SN250 knock in strains were compared in RPMI+1% BCS at 37°C at 24 and 48 hr. Asterisks indicate statistically significant differences between the indicated strain and SN250 by ANOVA followed by Dunnett’s correction for multiple comparisons (P <0.05).