Photosynthesis nuclear genes generally lack TATA-boxes: a tobacco photosystem I gene responds to light through an initiator.
The promoter architecture of the nuclear-encoded photosystem I genes was studied using a tobacco gene, psaDb, as a model case. Linker scanning mutations revealed that the psaDb promoter does not have a TATA box. Instead, pyrimidine-rich Initiator (Inr) elements that overlap the transcription start sites are essential for light-responsive transcription of this gene. When the psaDb promoter was mutated to have a TATA-box but no Inr, light-responsive transcription was impaired, indicating that the regulatory system of this gene prefers Inr to a TATA box. As very little is known about plant TATA-less promoters, we subsequently examined whether this promoter architecture is unique to psaDb. Computer analysis of 232 plant promoters revealed surprising features; the majority of photosynthesis nuclear genes lacked TATA boxes, although the frequency of the TATA-less promoters in non-photosynthesis genes was less than 10%. These results strongly suggest that TATA-independent transcription mechanisms play important roles in the regulated expression of photosynthesis nuclear genes.
Nakamura
Masayuki
M
Center for Gene Research, Nagoya University, Nagoya 464-8602, Japan.
Tsunoda
Tatsuhiko
T
Obokata
Junichi
J
D024506:5' Flanking Region / Q000235:genetics; D001483:Base Sequence; D003624:Darkness; D018506:Gene Expression Regulation, Plant; D008027:Light; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics*; D010788:Photosynthesis / Q000235:genetics*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics* / Q000378:metabolism; D045331:Photosystem I Protein Complex; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D016385:TATA Box / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics* / Q000502:physiology; D024363:Transcription Initiation Site
D009687:Nuclear Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D011993:Recombinant Fusion Proteins; D008156:Luciferases