On 2015 Sep 06, Martine Crasnier-Mednansky commented:

This review should have discussed transcription-coupled DNA supercoiling. Ma J, 2013 demonstrated that RNAP was fully capable of melting DNA at random, and indicated that RNAP-generated (-) supercoiling may facilitate initiation of transcription at adjacent promoters and binding of regulatory proteins. This agrees with the proposal CRP-cAMP has a preferential affinity for negatively supercoiled promoters. The same authors also indicated in vivo transcription-generated supercoiling may potentially dissociate DNA-bound proteins even at a distance. Thus current understanding suggests RNAP itself may have evolved to be a master regulator of gene expression. Simply said, transcriptional regulators do not recruit RNAP, they are recruited by RNAP.

On 2015 Sep 06, Martine Crasnier-Mednansky commented:

This review should have discussed transcription-coupled DNA supercoiling. Ma J, 2013 demonstrated that RNAP was fully capable of melting DNA at random, and indicated that RNAP-generated (-) supercoiling may facilitate initiation of transcription at adjacent promoters and binding of regulatory proteins. This agrees with the proposal CRP-cAMP has a preferential affinity for negatively supercoiled promoters. The same authors also indicated in vivo transcription-generated supercoiling may potentially dissociate DNA-bound proteins even at a distance. Thus current understanding suggests RNAP itself may have evolved to be a master regulator of gene expression. Simply said, transcriptional regulators do not recruit RNAP, they are recruited by RNAP.