12 Results
for author "Richard L. Bennett"
Figure 1Known white–opaque regulatory circuitry. (A) Typical white and opaque cells grown in liquid culture. Bar, 5 µm. (B) Typical white (left) and opaque (right) colonies. (C and D) Regulatory circuit in (C) white and (D) opaque cells based on binding events identified in previously published ChIP studies of key regulators of switching (Zordan et al. 2007; Hernday et al. 2013, 2016; Lohse et al. 2013; Lohse and Johnson 2016). The charts indicate which regulators were enriched at the control region of each regulator. Dark boxes indicate binding of the regulator at a given regulatory region, while empty boxes indicate a lack of significant binding.
Figure 2Identification of new regulators that affect white-to-opaque or opaque-to-white switching. (A) White-to-opaque switching frequencies for 191 regulators, normalized to the average of five wild-type switching assays performed the same day. (B) Opaque-to-white switching frequencies for 188 regulators, normalized to the average of five wild-type switching assays from the same day. (C) Comparison of normalized white-to-opaque and opaque-to-white switching rates for 186 regulators (Pearson’s r, −0.15; Spearman’s rho, −0.04). A value of 1 represents switching at the wild-type rate, values <1 reflect reduced switching, and values >1 reflect increased switching. Axes are plotted on a log2 scale.
Figure 3There is no overall correlation between growth rate and switching. (A) Comparison of normalized white-to-opaque switching frequencies and normalized white cell maximum growth rate for 191 strains (Pearson’s r, −0.29; Spearman’s rho, 0.21). (B) Comparison of normalized opaque-to-white switching frequencies and normalized opaque cell maximum growth rate for 187 strains (Pearson’s r, 0.21; Spearman’s rho, 0.21). (C) Comparison of the normalized white cell maximum growth rate and the normalized opaque cell maximum growth rate for 185 strains (Pearson’s r, 0.54; Spearman’s rho, 0.38). Normalized switching rates are plotted on a log2 scale and normalized maximum growth rates are plotted on a linear scale.
Figure 4Identification of new regulators of opaque cell morphology. (A) Images of typical wild-type opaque cells. (B) Images of three deletion mutants that result in a shorter, fatter, more oval opaque cell morphology. Bars, 10 µm.
Figure 5Regulators of selected processes whose deletion affects either white-to-opaque or opaque-to-white switching at least threefold. The direction(s) of each regulator’s effect is indicated. It was only possible to screen switching in one direction for regulators marked with *.
Figure 6Analysis of regulators that function in specific metabolic complexes or pathways. (A) Effects of deleting various members of the C. albicans CCAAT complex on white-to-opaque switching. (B) Deletion of either member of the C. albicans Ino2/4 dimer reduces white-to-opaque switching rates. The ino4 mutant was constructed in the strain background corresponding to the left wild-type sample; the ino2 mutant was constructed in the strain background corresponding to the right wild-type sample. In both panels, the mean and SD of four (mutant) or five (wild type) independent replicates from the same day are plotted. Data in both panels are normalized to the white-to-opaque switching rates of the matched wild-type control strain from the same day. Strains marked with an * have switching rates that are significantly different relative to their corresponding wild-type strains (Welch’s t-test, two tailed, P < 0.01).
Figure 1Genomic and phylogenetic position of EFG1 in C. tropicalis. (A) Schematic depiction of the genomic location of EFG1 in C. albicans and the corresponding genomic location in C. tropicalis. (B) As (A), but for C. tropicalis EFG1 and the corresponding location in C. albicans. In (A and B) the upper panel depicts C. albicans chromosomes (green background) and the lower panel depicts C. tropicalis chromosomes (blue background). Coordinates are in kb. One-to-one orthologs defined by CGOB are shown using the same color and are connected by dashed gray lines if in the same panel. The prefixes “orf19.” and “CTRG_” for C. albicans and C. tropicalis ORF names, respectively, were omitted. The white segment at the bottom of the C. tropicalis EFG1 gene depicts the location of the sequence gap. (C) Gene phylogeny of the EFG1 and EFH1 genes in the CTG clade and S. cerevisiae. Ortholog sequences were obtained from CGOB (Maguire et al. 2013), aligned using MUSCLE, and a phylogenetic tree was generated using PhyML in Seaview (Gouy et al. 2010). Branch support values are SH-like approximate likelihood ratios and the branch-length scale bar represents substitutions per site. Generating the tree by bootstrapping (100 trees) gave the same tree topology. The species relationships depicted in the cladogram (lower right) were obtained from (Maguire et al. 2013).
Figure 2EFG1 is involved in filamentation and biofilm formation in C. tropicalis. (A) Formation of filamentous cells by wild-type and EFG1 deletion strains of C. tropicalis in the MYA3404 genetic background. Representative DIC microscopy images are shown for each time point. Scale bars are 5 μm. (B) Images of representative biofilms for EFG1 deletion mutants in C. albicans and C. trpicalis (two independent isolates) grown in wells of six-well polystyrene plates. (C) Biomass dry weights of the same strains shown in (B), grown in the same conditions. Error bars represent the SD of five replicates.