Fig 3.

Regulation of CPK biosynthesis involves a gamma-butyrolactone and interplay with other biosynthetic pathways. Genes associated with the cpk cluster are indicated by large open arrows. Regulatory interactions are indicated by bold arrows (activation steps) or bold lines ending with a bar (repressing or inhibitory steps). Small-molecule ligands are indicated in colored letters, with ACT and RED being the products of other pathways encoded by distant gene clusters. For further explanation and references, see the text.