LOS2, a genetic locus required for cold-responsive gene
transcription encodes a bi-functional enolase.
Lee H, Guo Y, Ohta M, Xiong L, Stevenson B, Zhu JK.
Department of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA.
The Arabidopsis mutation, los2, impairs cold-responsive gene transcription,
acquired freezing tolerance and plant resistance to chilling under certain
conditions. LOS2 was isolated through positional cloning and shown to encode an
enolase in the glycolytic pathway. In animal cells, enolase has also been known
to function as a transcription factor that represses the expression of c-myc by
binding to the c-myc gene promoter. LOS2 fused to green fluorescent protein is
targeted to the nucleus as well as to the cytoplasm. LOS2/enolase protein can
bind to the cis-element of the human c-myc gene promoter and to the gene
promoter of STZ/ZAT10, a zinc finger transcriptional repressor from Arabidopsis.
STZ/ZAT10 expression is induced rapidly and transiently by cold in the wild
type, and this induction is stronger and more sustained in the los2 mutant.
Furthermore, the expression of a RD29A-LUC reporter gene is repressed
significantly by STZ/ZAT10 in transient expression assays in Arabidopsis leaves.
Our results demonstrate that cold-responsive gene transcription in plants is
controlled by a bi-functional enolase.