Role of two NtcA-binding sites in the complex ntcA gene promoter of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120.
Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that fixes N(2) in specialized cells called heterocysts, which differentiate from vegetative cells in a process that requires the nitrogen control transcription factor NtcA. 2-Oxoglutarate-stimulated binding of purified NtcA to wild-type and modified versions of the ntcA gene promoter from Anabaena sp. was analyzed by mobility shift and DNase I footprinting assays, and the role of NtcA-binding sites in the expression of the ntcA gene during heterocyst differentiation was studied in vivo by using an ntcA-gfp translational fusion and primer extension analysis. Mutation of neither of the two identified NtcA-binding sites eliminated localized expression of ntcA in proheterocysts, but mutation of both sites led to very low, nonlocalized expression.
Olmedo-Verd
Elvira
E
Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas, Universidad deSevilla, E-41092 Seville, Spain.
Valladares
Ana
A
Flores
Enrique
E
Herrero
Antonia
A
Muro-Pastor
Alicia M
AM
D017033:Anabaena; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D018983:DNA Footprinting / Q000379:methods; D003850:Deoxyribonuclease I / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics*; D007656:Ketoglutaric Acids / Q000494:pharmacology; D009154:Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding / Q000187:drug effects
D001426:Bacterial Proteins; D007656:Ketoglutaric Acids; D003850:Deoxyribonuclease I