REGULATION OF ARABIDOPSIS-THALIANA L (HEYN) COR78 IN RESPONSE TO LOW-TEMPERATURE

Changes in gene expression occur during cold acclimation in a variety of plants including Arabidopsis thaliana L. (Heyn). Here we examine th e cold-regulated expression of A. thaliana cor78. The results of gene- fusion experiments confirm the finding of Yamaguchi-Shinozaki and Shin ozaki ([1993] Mol Gen Genet 236: 331-340) that the 5' region of cor78 has cis-acting regulatory elements that can impart cold-regulated gene expression. Further, histochemical staining experiments indicated tha t this cold-regulatory element(s) was active at low temperature throug hout much of the plant including leaves, stems, roots, flower petals, filaments, and sepals. Time-course experiments indicated that the acti vity of the cor78 promoter in cold-acclimated plants was down-regulate d quickly in response to noninducing temperatures and that the half-li fe of the cor78 transcripts was only about 40 min at normal growth tem perature. Fusion of the entire transcribed region of cor78 to the caul iflower mosaic virus 35S promoter resulted in a chimeric gene that was constitutively expressed and displayed little if any posttranscriptio nal regulation in response to low temperature.