Signals from chloroplasts converge to regulate nuclear gene expression.
Plastid-to-nucleus retrograde signaling coordinates nuclear gene expression with chloroplast function and is essential for the photoautotrophic life-style of plants. Three retrograde signals have been described, but little is known of their signaling pathways. We show here that GUN1, a chloroplast-localized pentatricopeptide-repeat protein, and ABI4, an Apetala 2 (AP2)–type transcription factor, are common to all three pathways. ABI4 binds the promoter of a retrograde-regulated gene through a conserved motif found in close proximity to a light-regulatory element. We propose a model in which multiple indicators of aberrant plastid function inArabidopsisare integrated upstream of GUN1 within plastids, which leads to ABI4-mediated repression of nuclear-encoded genes.
Koussevitzky
Shai
S
Howard Hughes Medical Institute, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
Nott
Ajit
A
Mockler
Todd C
TC
Hong
Fangxin
F
Sachetto-Martins
Gilberto
G
Surpin
Marci
M
Lim
Jason
J
Mittler
Ron
R
Chory
Joanne
J
D000040:Abscisic Acid; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism* / Q000382:microbiology*; D002736:Chloroplasts / Q000378:metabolism*; D018744:DNA, Plant / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004579:Electron Transport; D018506:Gene Expression Regulation, Plant; D045342:Light-Harvesting Protein Complexes / Q000235:genetics; D008034:Lincomycin / Q000494:pharmacology; D008954:Models, Biological; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D011524:Protoporphyrins / Q000378:metabolism; D011724:Pyridazines / Q000494:pharmacology; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism*
C470421:ABI4 protein, Arabidopsis; D029681:Arabidopsis Proteins; D018744:DNA, Plant; D004268:DNA-Binding Proteins; C519677:GUN1 protein, Arabidopsis; D045342:Light-Harvesting Protein Complexes; D011524:Protoporphyrins; D011724:Pyridazines; D014157:Transcription Factors; C039629:magnesium protoporphyrin; D000040:Abscisic Acid; D008034:Lincomycin; C028025:protoporphyrin IX; C008677:norflurazone