Characterization of the light-responsive promoter of rice chloroplast psbD-C operon and the sequence-specific DNA binding factor.
The transcription of rice plastid psbD-psbC genes encoding photosystem II reaction center protein D2 and chlorophyll alpha-binding protein CP43 is closely regulated by light. To elucidate the sequence requirement for the light-responsive promoter of psbD-psbC operon, transcriptional analysis of the rice promoter was performed with deleted mutants and site-directed mutants in vitro. Deletion of -546 approximately -100 upstream sequences resulted in 4- to 5-fold decrease in the transcription rate. Further deletion of -99 approximately -40 conserved region of repeated sequences resulted in 2-fold decrease in the transcription rate. The core light-responsive promoter requires "-10" element but not "-35" element for accurate initiation of basal transcription. No downstream promoter element was found in the +4 approximately +111 region. The competitive gel-retardation experiments revealed the presence of DNA-binding protein in the rice chloroplasts, which interacts specifically with the -60 approximately -37 repeated sequences. Southwestern blot analysis further demonstrated that the binding factor is composed of 36-kDa polypeptide(s).
To
K Y
KY
Institute of Botany, Academia Sinica, Nankang, Taipei, Taiwan, Republic of China.
Cheng
M C
MC
Suen
D F
DF
Mon
D P
DP
Chen
L F
LF
Chen
S C
SC
D001483:Base Sequence; D002736:Chloroplasts; D018744:DNA, Plant; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D008027:Light; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D009876:Operon; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics*; D045332:Photosystem II Protein Complex; D010936:Plant Extracts; D011401:Promoter Regions, Genetic
D018744:DNA, Plant; D004268:DNA-Binding Proteins; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010936:Plant Extracts