Genes involved in sulfur metabolism controlled by premature termination of transcription via a T-box or an S-box system. 5' untranslated region containing a T-box or an S-box motif are indicated by black or grey boxes, respectively. Loops indicate putative transcriptional terminators. Striped boxes indicate the genes encoding transporters. The genes involved in cysteine biosynthesis are indicated by dotted boxes while the SAM synthase gene, metK, is indicated by a checkerboard box. The expression ratios (homocysteine/cystine) obtained in transcriptome analysis are indicated under the genes while the expression ratios (homocysteine/cystine) obtained by qRT-PCR are indicated in parentheses. An alignment of the S-box motif of metT and metK has been previously published .