Transcription of the Anabaena sp. strain PCC 7120 ntcA gene: multiple transcripts and NtcA binding

The Anabaena sp. strain PCC 7120 ntcA gene showed multiple transcripts with different 5' ends. The relative abundance of transcripts varied in response to nitrogen availability. The ntcA product, NtcA, showed binding to the promoter region of its own gene. The binding site mapped to a region between the transcription start site used under nitrogen-replete conditions and the start sites used under nitrogen-limiting conditions, suggesting that NtcA regulates its own expression.