Supporting Online Materials for Pedraza Et Al. Noise Propagation in Gene Networks

Construction of the synthetic network The network shown in Fig. 1A is implemented in Escherichia coli using the plasmid pJM31 (Fig. S1). This plasmid contains all components of the network except the lactose repressor gene, lacI, that is integrated in the E. coli genome under the strong promoter PlacIq (1). The fluorescent proteins were obtained from the plasmids pECFP, pEYFP, and pDsRed-Express (Clontech). The promoters Ptet and Plac were amplified from the plasmids pZE21-MCS2 and pZE12-luc (2), respectively (gift of R. Lutz and H. Bujard). The tetracycline repressor gene tetR was obtained from pIKE108 (3, gift of T. S. Gardner and J. J. Collins). The strong constitutive promoter PL and the transcription terminator aspA were obtained from plasmid pLEX (Invitrogen). The T1T2 transcription terminator, the ampicillin gene, and the colE1 origin of replication were obtained from PZE12-luc (2).