Gene expression of GidA mutant Streptococcus pyogenes

In Streptococcus pyogenes, mutation of GidA results in avirulence despite the same growth rate as the wild type. To understand the basis of this effect, global transcription profiling was conducted. Keywords: Wild type vs. GidA mutant Streptococcus pyogenes A S. pyogenes genespecific microarray, consisting of 60 to 80-mer oligonucleotides representing 1517 genes out of a total of 1752 predicted open reading frames in the SF370 genome, was constructed. S. pyogenes wild type strain (HSC5) or TM-GidA2 strain (GidA mutant derived form the wild type strain HSC5) were grown in Todd-Hewitt broth supplemented with 0.2% yeast extract (THY medium) to mid-logarithmic phase of growth (OD600=0.3). RNA was extracted, amplified, and hybridized to the arrays. Each experiment consisted of a pair-wise competitive hybridization of amplified RNA samples from the wild type and GidA mutant derived RNA. Since 2 biological replicates were tested in duplicate with a reciprocal dye-flip, a total of eight DNA microarrays were used for comparison for each set of RNA amplifications.