Figure 4.

Transcript analysis of the ery cluster and regulatory genes. (A) Microarray analysis. Visualization by dChip of the expression of the ery cluster (upper panels) and regulatory genes (lower panels) during the time course of the wild type strain (right panels) and during phase a in the wild type and the rif1 and rif6 mutants (left panels). Red = up-regulation; Green = down-regulation. (B). Semi-quantitative analysis of eryCII- and bldD-specific transcripts by RT real-time PCR. The RNAs were extracted from S. erythraea NRRL2338 and rif derivatives rif1 and rif6 grown in R3/1 medium up to phase a. Results were normalized to 16S rRNA levels. Transcript levels of S. erythraea NRRL2338 were arbitrarily given a value of 1. Data are shown as mean ± standard deviation from three independent experiments, each with triplicate samples, using distinct cDNA preparations for each RNA sample. The Student's t-test was used for statistical analysis. Statistically significant differences between values from S. erythraea NRRL2338 and rif mutants (asterisks) are declared at a p value < 0.05.