K.Brinkrolfetal./JournalofBiotechnology149 (2010) 173–182

179

Fig.3.Transcriptionregulatorsandtranscriptionalregulatoryinteractionsinvolvedincontrollingtheconversionofthesugarsubstratessucrose,glucoseandfructoseintotheaminoacidsl-lysineandl-glutamateinC.glutamicumATCC13032.Relevantmetabolicpathwaysareshownschematically.Reactionsinvolvedinglycolysisandthecitratecycleareshownbyblackarrowsandarelabeledbygenenames.Thesixkeygenesdetectedby“genomebreeding”arespeci callymarkedinred.Colourcode:rednode,repressor;greennode,activator;bluenode,dualregulator;yellownode,sigmafactor;dark-graynode,targetgene;light-graynode,genewithoutregulation;redline;repression;greenline,activation;graytrianglenode,antisenseRNA;greendashedline,positivecontrolbyantisenseRNA.

aconitasegeneacnandthesdhABCoperonencodingsuccinatedehydrogenase(Fig.3).Accordingly,acnandsdhABCareappro-priatecandidatesforso-calledintermodulargenes,integratingsignalsattheirpromotersitescomingfromdifferentfunctionalmodulsofthecell(Freyre-Gonzálezetal.,2008).Thereconstruc-tionalsoshowsdifferentexecutivelevelsandthusamulti-layeredhierarchyinthispartoftheC.glutamicumregulatorynetwork(Fig.3).