title: Pathogen-induced binding of the soybean zinc finger homeodomain proteins GmZF-HD1 and GmZF-HD2 to two repeats of ATTA homeodomain binding site in the calmodulin isoform 4 (GmCaM4) promoter.
abstract: Calmodulin (CaM) is involved in defense responses in plants. In soybean (Glycine max), transcription of calmodulin isoform 4 (GmCaM4) is rapidly induced within 30 min after pathogen stimulation, but regulation of the GmCaM4 gene in response to pathogen is poorly understood. Here, we used the yeast one-hybrid system to isolate two cDNA clones encoding proteins that bind to a 30-nt A/T-rich sequence in the GmCaM4 promoter, a region that contains two repeats of a conserved homeodomain binding site, ATTA. The two proteins, GmZF-HD1 and GmZF-HD2, belong to the zinc finger homeodomain (ZF-HD) transcription factor family. Domain deletion analysis showed that a homeodomain motif can bind to the 30-nt GmCaM4 promoter sequence, whereas the two zinc finger domains cannot. Critically, the formation of super-shifted complexes by an anti-GmZF-HD1 antibody incubated with nuclear extracts from pathogen-treated cells suggests that the interaction between GmZF-HD1 and two homeodomain binding site repeats is regulated by pathogen stimulation. Finally, a transient expression assay with Arabidopsis protoplasts confirmed that GmZF-HD1 can activate the expression of GmCaM4 by specifically interacting with the two repeats. These results suggest that the GmZF-HD1 and -2 proteins function as ZF-HD transcription factors to activate GmCaM4 gene expression in response to pathogen.
authors.affiliation: Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, Korea.
authors.forename: Hyeong Cheol
authors.initials: HC
authors.lastname: Park
authors.forename: Man Lyang
authors.initials: ML
authors.lastname: Kim
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Lee
authors.forename: Jeong Dong
authors.initials: JD
authors.lastname: Bahk
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
authors.forename: Chae Oh
authors.initials: CO
authors.lastname: Lim
authors.forename: Jong Chan
authors.initials: JC
authors.lastname: Hong
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Moo Je
authors.initials: MJ
authors.lastname: Cho
authors.forename: Woo Sik
authors.initials: WS
authors.lastname: Chung
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002147:Calmodulin / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013025:Glycine max / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D020080:Tandem Repeat Sequences; D015533:Transcriptional Activation; D016335:Zinc Fingers
chemical_list: D002147:Calmodulin; D018076:DNA, Complementary; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D020033:Protein Isoforms