Dissection of 5' upstream sequences for selective expression of the Nicotiana plumbaginifolia rbcS-8B gene.
We have previously isolated and characterized a gene (rbcS-8B) from the wild-type species Nicotiana plumbaginifolia, encoding the small subunit of ribulose-1,5-bisphosphate carboxylase. Using transgenic N. plumbaginifolia as a host, we found that a 5' upstream region (-1038 to +32) of rbcS-8B contains all the sequences required for organ-specific and light-dependent expression of the gene. Here we report a detailed analysis of the 5' upstream region of rbcS-8B. Gene transfer experiments indicate that the region between -1038 to -102 contains at least two enhancer-like elements. The proximal element located between -312 and -102, confers organ-specific and light-inducible expression upon a reporter gene and closely resembles previously identified elements in other light-responsive plant genes. The distal element with novel characteristics is located between -1038 and -589. It can enhance expression from the cauliflower mosaic virus 35S promoter, but only when the -90 to -46 region of the 35S promoter is present. It confers on the heterologous promoter the organ-specificity of a typical rbcS gene but the enhanced transcription in leaves is insensitive to light. These experiments show for the first time that organ-specificity and light-responsiveness can be determined by separable cis-regulatory elements. The implications for the regulation of light-responsive genes are discussed.
Poulsen
C
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Laboratory of Plant Molecular Biology, Rockefeller University, New York, NY 10021-6399.
Chua
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NH
D000595:Amino Acid Sequence; D001483:Base Sequence; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004742:Enhancer Elements, Genetic; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010777:Photochemistry; D010947:Plants, Toxic; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics*; D014026:Nicotiana / Q000235:genetics*; D014170:Transformation, Genetic
D015500:Chloramphenicol O-Acetyltransferase; D012273:Ribulose-Bisphosphate Carboxylase