Comparative Global Gene Expression Profiles of Wild-Type Yersinia pestis CO92 and Its Braun Lipoprotein Mutant at Flea and Human Body Temperatures
Figure 1
Hierarchical clustering of genes determined to be significantly altered in the lpp mutant of Y. pestis CO92 cultured at relative to the WT bacteria. (a) Heat map showing clustering of genes differentially expressed between the Y. pestis lpp mutant, compared to WT bacteria, is presented. Clustering was performed on normalized and log-transformed hybridization signals using CLUSFAVOR 6.0 (Baylor College of Medicine, Houston, TX). The three replicate samples representing the two experimental conditions (Y. pestis CO92 or its lpp mutant) are labeled as WT and Lpp, respectively. Note that the two experimental conditions clustered apart from one another, and altered genes collectively exhibited a pronounced difference in signal intensity. The vertical dendrograms indicate relative similarity between samples (columns), while the horizontal dendrograms indicate clusters of genes (rows). Bright red indicates the highest normalized intensity value, bright green the lowest, and black median values. (b) Graphical representation of the cluster shown in panel (a). Normalized signal intensity values are shown on the ordinate, and experimental conditions are listed on the abscissa. The blue bars represent the range of normalized, log-transformed signal intensities for the entire group of genes while the red line indicates the median signal and thus the trend of gene expression differences. As shown, the average and median signal intensities for this group of genes is lower in the Y. pestis lpp mutant, compared to the WT bacteria.
