RsiG is an anti-sigma factor that binds and sequesters the sporulation-specific sigma factor WhiG in a fashion dependent on 3',5'-cyclic diguanylic acid (c-di-GMP). RsiG can bind the cyclic dinucleotide in the absence of sigma factor WhiG, and does so in a specific manner via a unique signature conserved in all Streptomyces. This gene was originally named amfC (aerial mycelium formation protein) but no specific role was established, and was later renamed rsiG (regulator of sigma WhiG).
Jiyao W et al.(2023). "The conserved domain database in 2023.",