Artificial combination of two cis-regulatory elements generates a unique pattern of expression in transgenic plants.
We show that a 36-base-pair-long upstream fragment from the soybean hsp17.3-B gene comprising two partly overlapping heat-shock element (HSE)-like sequences can confer heat inducibility to a reporter gene in transgenic tobacco. The heat-shock response does not display organ specificity and is not affected by light. Insertion of these HSE-like elements into the pea rbcS-3A 5' flanking fragment (position -410 to +15) either at position -410 (5' to the enhancer) or at position -49 (between the enhancer and the "TATA" box) renders the transcript level of the reporter gene light-inducible and organ-specific under heat-shock conditions. These results demonstrate the possibility of generating a unique pattern of expression (e.g., light-dependent and organ-specific heat-shock response) by artificial combination of appropriate cis-acting regulatory elements. Moreover, by using the HSE-like sequences as a weak heat-inducible enhancer in the chimeric regulatory regions we uncover the function of negative elements within the pea rbcS-3A upstream region. These negative elements are responsible for a repressed transcript level in roots as well as in dark-adapted leaves. Therefore, the upstream fragment containing two HSE-like elements can be considered a useful tool to test the function of other cis-acting elements.
D005786:Gene Expression Regulation / Q000528:radiation effects; D006360:Heat-Shock Proteins / Q000235:genetics*; D006358:Hot Temperature; D008027:Light; D010940:Plant Proteins / Q000235:genetics*; D010947:Plants, Toxic; D012045:Regulatory Sequences, Nucleic Acid; D014018:Tissue Distribution; D014026:Nicotiana / Q000235:genetics*; D014157:Transcription Factors / Q000502:physiology; D014162:Transfection
D006360:Heat-Shock Proteins; D010940:Plant Proteins; D014157:Transcription Factors