AtBI-1, a plant homologue of Bax inhibitor-1, suppresses Bax-induced cell death in yeast and is rapidly upregulated during wounding and pathogen challenge.
Extensive searches have so far failed to identify functional plant homologues of the mammalian apoptotic machinery. Here we report the isolation and characterisation of an Arabidopsis thaliana homologue of human Bax Inhibitor-1, AtBI-1, isolated during a differential screen of plants challenged with the phytopathogen Pseudomonas syringae. AtBI is a member of a small gene family in Arabidopsis, members of which display extensive amino acid identity to human BI-1. AtBI-1 is also functionally similar to BI-1 in its ability to suppress the lethal phenotype in yeast conferred by expression of the mammalian proapoptotic protein, Bax. Expression of AtBI-1 is rapidly upregulated in plants during wounding or pathogen challenge, suggesting a role in responses to biotic and abiotic stress. AtBI-1 upregulation appears R gene independent and is not markedly affected by mutations required for specific classes of R genes. However, the accumulation of AtBI-1 message is significantly reduced in coi1, in which defence responses to insects, pathogens and wounding are compromised.
Sanchez
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P
Department of Biological Sciences, Wye College, Wye, Kent TN25 5AH, UK.
de Torres Zabala
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M
Grant
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M
D000595:Amino Acid Sequence; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D017360:Arabidopsis / Q000235:genetics / Q000382:microbiology / Q000502:physiology*; D029681:Arabidopsis Proteins; D016923:Cell Death; D018506:Gene Expression Regulation, Plant; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000502:physiology; D011506:Proteins; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D019253:Proto-Oncogene Proteins c-bcl-2; D011549:Pseudomonas / Q000472:pathogenicity; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014774:Virulence; D051028:bcl-2-Associated X Protein
C491862:ATBI-1 protein, Arabidopsis; D051017:Apoptosis Regulatory Proteins; D029681:Arabidopsis Proteins; C494826:BAX protein, human; D008565:Membrane Proteins; D010940:Plant Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C484209:TMBIM6 protein, human; D051028:bcl-2-Associated X Protein