Two dehydration-inducible transcripts from the resurrection plant Craterostigma plantagineum encode interacting homeodomain-leucine zipper proteins.
The molecular dissection of desiccation tolerance in the resurrection plant Craterostigma plantagineum led to the isolation of two dehydration-stress inducible homeo-domain-leucine zipper genes (CPHB-1 and -2). When the coding region of CPHB-1 was used as bait in the yeast two-hybrid system, the ability of CPHB-1 to form homodimers was demonstrated. The two-hybrid system was also used to isolate CPHB-2, which heterodimerises with CPHB-1. Both transcripts are inducible by dehydration in leaves and roots, but steady state levels vary in response to exogenously applied ABA. Although expression of CPHB-1 is not inducible by ABA, the transcript level of CPHB-2 increases during ABA-treatment. Both genes are expressed at very early stages of dehydration and thus may be involved in the regulation of gene expression during dehydration. CPHB-1 and -2 differential expression in response to ABA suggests that they act in different branches of the dehydration-induced signalling network. In vitro binding studies revealed that CPHB-1 specifically binds to the pseudopalindromic sequence CAAT(C/G)ATTG. Using this element for in vitro binding studies with nuclear proteins from dehydrated leaves, an inducible DNA-protein complex was identified.
Frank
W
W
Max-Planck-Institut für Züchtungsforschung, Köln, Germany.
Phillips
J
J
Salamini
F
F
Bartels
D
D
D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D018744:DNA, Plant / Q000235:genetics / Q000302:isolation & purification; D019281:Dimerization; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005801:Genes, Homeobox; D017343:Genes, Plant; D018398:Homeodomain Proteins / Q000737:chemistry / Q000235:genetics*; D016350:Leucine Zippers / Q000235:genetics; D019684:Magnoliopsida / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism
D017931:DNA Primers; D018076:DNA, Complementary; D018744:DNA, Plant; D018398:Homeodomain Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D000040:Abscisic Acid