NtcA Regulates <i>patA</i> Expression in <i>Anabaena</i> sp. Strain PCC 7120

Abstract

patA expression is induced 3 to 6 h after nitrogen step-down. We establish that the transcription of patA is under the positive control of NtcA. The patA promoter region shows two conserved NtcA-binding boxes. These NtcA-binding sites and their interaction with NtcA are key elements for patA expression in heterocysts.