Nucleic Acids Research, 1987, Vol. 15, No. 20 8267-8281
© 1987
Articles |
Plant expression signals of the Agrobacterium T-cyt gene
Molbas Research Group, Department of Plant Molecular Biology, Leiden University Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
*To whom correspondence should be addressed
Received July 17, 1987. Revised September 25, 1987. Accepted September 25, 1987.
Within the 5' and 3' non-coding regions of the T-cyt gene from the oc-topine T-DNA of Agrobacterium tumefaciens sequences required for expression of this gene in plant cells were identified by deletion mutagenesis. The results show that 184 bp of the 5' non-coding region and 270 bp of the 3' non-coding region are sufficient for wild-type expression. Within the 5' non-coding region two essential expression signals were identified: (1.) an activator element located between -185 and -129 with respect to the ATG start codon and (2.) one out of two TATA boxes. Deletions of the activator element or the two TATA boxes resulted in nonfunctional genes. Deletion of the upstream TATA box and both putative CAAT boxes did not significantly affect expression. Within the 3' non-coding region, the polyadenylation box most distal to the stop codon was not essential for expression, but sequences more upstream, including a second polyadenylation box were found to be required for wild-type expression.