Regulation of BN115, a low-temperature-responsive gene from winter Brassica napus.
The genomic clone for BN115, a low-temperature-responsive gene, was isolated from winter Brassica napus and its sequence was determined. A 1.2-kb fragment of the 5' regulatory region (from bp -1107 to +100) was fused to the beta-glucuronidase (GUS) reporter gene and BN115-promoted GUS expression was observed in green tissues of transgenic B. napus plants only after incubation at 2 degrees C. No expression was observed after incubation at 22 degrees C, either in the presence or the absence of ABA. Microprojectile bombardment of winter B. napus leaves with a BN115 promoter/GUS construct yielded similar results and was used to analyze a series of deletions from the 5' end of the promoter. Results obtained from transient expression studies showed that the low-temperature regulation of BN115 expression involves a possible enhancer region between bp -1107 and -802 and a second positive regulatory region located between bp -302 and -274. Deletion analyses and results from replacement with a truncated cauliflower mosaic virus 35S promoter suggest that the minimal size required for any maintenance of low-temperature GUS expression is a -300-bp fragment. Within this fragment are two 8-bp elements with the sequence TGGCCGAC, which are identical to those present in the positive regulatory region of the promoter of the homologous Arabidopsis cor15a gene and to a 5-bp core sequence in the low-temperature- and dehydration-responsive elements identified in the promoter regions of several cold-responsive Arabidopsis thaliana genes.
White
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TC
Plant Research Centre, Agriculture Canada, Ottawa, Ontario.
Simmonds
D
D
Donaldson
P
P
Singh
J
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D001937:Brassica / Q000235:genetics* / Q000502:physiology; D003001:Cloning, Molecular; D003081:Cold Climate; D017931:DNA Primers; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005966:Glucuronidase / Q000096:biosynthesis; D008969:Molecular Sequence Data; D018515:Plant Leaves; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D012621:Seasons; D017384:Sequence Deletion
D017931:DNA Primers; D005966:Glucuronidase