DNA-binding factors assemble in a sequence-specific manner on the maize mitochondrial atpA promoter.
The maize mitochondrial atpA promoter has been well-characterized using in vitro transcription. The functional elements of this promoter comprise a central domain extending from -7 to +5 relative to the transcription start site, and an upstream domain of 1-3 bp that is purine-rich and centered around positions -11 to -12. As a first step in characterizing the transcriptional machinery, exonuclease-III mapping (toeprinting) was used to map the borders of DNA-protein interactions using either a 107-bp wild-type template or transcriptionally-inactive templates containing linker-scanning mutations. These experiments revealed that, with a wild-type promoter, protein factors occupy as much as 36 bp, from positions -20 to +16 relative to the transcription initiation site. Protein-binding patterns were altered when the linker-scanning mutants were used, suggesting that either the number or conformation of DNA-binding proteins could account for their inability to promote transcription initiation.
Chang
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Boyce Thompson Institute for Plant Research, Cornell University, Tower Road, Ithaca, NY 14853-1801, USA.
Stern
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DB
D001483:Base Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics*; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D006180:Proton-Translocating ATPases / Q000235:genetics* / Q000378:metabolism; D003313:Zea mays / Q000235:genetics*
D004268:DNA-Binding Proteins; D010940:Plant Proteins; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; D006180:Proton-Translocating ATPases