New insights into the pleiotropic drug resistance network from genome-wide characterization of the YRR1 transcription factor regulation system - PubMed (original) (raw)

Genes upregulated by YRR1. (A) Microarray results for the gain-of-function mutant and chimera experiments were analyzed by PCA (11) to determine the two key variables plotted on the two axes (PCA1 versus PCA2). This method clearly distinguished repressed genes (left, green) from activated genes (right, red) and the majority of genes not regulated by YRR1 (central, black). Genes specifically activated in the chimera experiments are marked in blue. The upregulated genes are distributed along a gradient, which may indicate the existence of different subgroups of genes. (B) Cluster analyses have been performed (12) and are shown here. The upper part of the diagram presents the results of six independent experiments in which a strain constitutively producing the gain-of-function mutant Yrr1p protein was compared with the SEY strain used as a control. The lower part of the diagram shows the results of three independent experiments in which the strain with the Yrr1*GAD construct was subjected to galactose induction for 4 h and compared with the wild-type FY strain, used as a control. Genes were identified as described in the text. The color scale is indicated in the lower part of the figure. The complete set of data is available at

http://www.biologie.ens.fr/yeast-publi.html

. (C) Time course of the expression of Yrr1p-regulated genes under galactose induction. Northern blot analyses were performed for each regulated gene identified by microarray experiments. Total RNA (10 μg) was deposited on the gel after induction in galactose medium for various lengths of time, from 30 min to 16 h. Three groups were defined according to the quantification profile obtained from Northern blot analysis (see the related website

http://www.biologie.ens.fr/yeast-publi.html

). For these three groups, mean RNA levels (arbitrary units) are plotted against the duration of galactose induction (in hours). Group 1 contains YLR046C, YLL056C, AZR1, SNG1, FLR1, YPL088W, and YLR179C, the most strongly induced genes. Group 2 comprises APD1, SNQ2, and PLB1, which display high levels of basal expression. Finally, group 3 consists of YGR035C, YMR102C, and YKL051W, which show an induction only after 2 h in galactose. Error bars are standard deviations.