Gibberellin-responsive elements in the promoter of a barley high-pI alpha-amylase gene.
AUTOR(ES)
Gubler, F
RESUMO
Deletion analysis has previously shown that the major gibberellic acid (GA)- and abscisic acid (ABA)-responsive elements in the promoter of a high-pI alpha-amylase gene of barley are located downstream of -174 (Jacobsen and Close, 1991). We have used transient expression assays in barley aleurone protoplasts to identify sequences between -174 and +53 that confer GA and ABA responsiveness on expression of a beta-glucuronidase reporter gene. Using alpha-amylase promoter fragments and synthetic oligonucleotides fused to minimal promoters, we have shown that the hormone-responsive region is located between -174 and -108. A single copy of this region fused to a minimal alpha-amylase promoter (-41) conferred both GA- and ABA-responsive expression on the reporter gene comparable to the positive control, Am(-174)IGN. Multiple copies of this region were able to activate even greater levels of expression. Site-directed mutagenesis was used to determine the functional importance of the conserved motifs (-169pyrimidine box, -143TAACAAA box, and -124TATCCAC box) and nonconserved intervening sequences within the region between -174 and -108. Our results showed that both the TAACAAA and TATCCAC boxes play an important role in GA-regulated expression. We propose that the TAACAAA box is a gibberellin response element, that the TATCCAC box acts cooperatively with the TAACAAA box to give a high level of GA-regulated expression, and that together these motifs form important components of a gibberellin response complex in high-pI alpha-amylase genes. The TAACAAA box also appears to be the site of action of ABA.(ABSTRACT TRUNCATED AT 250 WORDS)
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=160230Documentos Relacionados
- Gibberellin-regulated expression of a myb gene in barley aleurone cells: evidence for Myb transactivation of a high-pI alpha-amylase gene promoter.
- Gibberellin treatment stimulates nuclear factor binding to the gibberellin response complex in a barley alpha-amylase promoter.
- The cis-acting gibberellin response complex in high pI alpha-amylase gene promoters. Requirement of a coupling element for high-level transcription.
- A gibberellin response complex in cereal alpha-amylase gene promoters.
- Genetic analysis of the promoter region of the Bacillus subtilis alpha-amylase gene.