Expression of a higher-plant chloroplast psbD promoter in a cyanobacterium (Synechococcus sp. strain PCC7942) reveals a conserved cis-element, designated PGT, that differentially interacts with sequence-specific binding factors during leaf development.
The chloroplast psbD gene, which encodes the D2 subunit of photosystem II, is regulated by a blue light-responsive promoter (BLRP). We tested the ability of different regions of the barley (Hordeum vulagare) BLRP to drive transcription of the lacZ reporter gene in genomic transformants of Synechococcus sp. strain PCC7942. The barley BLRP was transcribed in Synechococcus from the same initiation sites that are used in plant chloroplasts in vivo. A region of the BLRP, residing between -83 and -112 bp upstream from the transcription initiation sites, functioned as a negative element in Synechococcus. Nucleotide sequences within this region are conserved among the psbD genes of several monocots and dicots, and with the nuclear negative regulatory element GT. Thus this new cis-element was designated Plastid GT, PGT. Proteins from chloroplasts of barley and Arabidopsis thaliana interacted with PGT in a sequence-specific and developmental-dependent manner. The DNA-protein complexes from Arabidopsis chloroplasts are composed of 60- and 38-kDa polypeptides. We postulate that GT and PGT have evolved in the nucleus and chloroplast, respectively, from a common ancestral regulatory element.
Christopher
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DA
Department of Plant Molecular Physiology, University of Hawaii at Manoa, 3190 Maile Way, Honolulu, HI 96822, USA. dchr@hawaii.edu
Shen
Y
Y
Dudley
P
P
Tsinoremas
N F
NF
D017360:Arabidopsis / Q000378:metabolism; D001483:Base Sequence; D017124:Conserved Sequence; D000458:Cyanobacteria / Q000235:genetics*; D018742:DNA, Chloroplast / Q000737:chemistry / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000528:radiation effects; D018506:Gene Expression Regulation, Plant / Q000528:radiation effects; D001467:Hordeum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008027:Light; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics* / Q000378:metabolism; D045332:Photosystem II Protein Complex; D018515:Plant Leaves / Q000254:growth & development; D010944:Plants / Q000235:genetics / Q000528:radiation effects; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D012689:Sequence Homology, Nucleic Acid; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D018742:DNA, Chloroplast; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D011993:Recombinant Fusion Proteins; D001616:beta-Galactosidase