A Novel Zinc Finger Protein Is Encoded by the Arabidopsis LSD1 Gene and Functions as a Negative Regulator of Plant Cell Death
Cell, Vol. 88, 685–694, March 7, 1997
Robert A. Dietrich, Michael H. Richberg,
Renate Schmidt, Caroline Dean,
and Jeffery L. Dangl
Summary
Arabidopsis lsd1 mutants are hyperresponsive to cell maminitiators and fail to limit the extent of cell death. Superoxide is a necessary and sufficient signal for cell death propagation. Thus, LSD1 onitors a superoxide-dependent signal and negatively regulates a plant cell death pathway.We isolated LSD1 via its map position. The predicted LSD1 protein contains three zinc finger domains, defined by CxxCxRxxLMYxxGASxVxCxxC. These domains are present in three additional Arabidopsis genes, suggesting that LSD1 defines a zinc finger protein subclass. LSD1 is constitutively expressed, consistent with the mutant phenotype. Alternate splicing gives rise to a low abundance mRNA encoding anextra five amino-terminal aminoacids.We propose that LSD1 regulates transcription, via either repression of a prodeath pathway or activation of an antideath pathway, in response to signals emanating from cells undergoing pathogen-induced hypersensitive cell death.