Ts. Ramasubramanian et al., ISOLATION OF THE ANABAENA SP STRAIN PCC-7120 SIGA GENE IN A TRANSCRIPTIONAL-INTERFERENCE SELECTION, Journal of bacteriology, 177(22), 1995, pp. 6676-6678
A transcriptional-interference selection was performed to identify gen
es of Anabaena sp. strain PCC 7120 that encode DNA-binding proteins ab
le to bind to the rbcL promoter. Unexpectedly, the selection yielded t
he previously identified sigA gene, which encodes the principal sigma
factor. Protein extracts from Escherichia coli containing the sigA gen
e bound the rbcL promoter fragment in mobility shift assays, and compe
tition experiments indicated binding to rbcL and glnA but not xisA or
nifH upstream regions.