Functional borders, genetic fine structure, and distance requirements of cis elements mediating light responsiveness of the parsley chalcone synthase promoter.
The genetic fine structure of cis-acting sequences previously shown to be necessary for light-regulated expression in the promoter of the parsley (Petroselinum crispum) chalcone synthase gene was analyzed. Site-directed mutations and changes in spacing between cis elements were measured in transient expression assays in parsley protoplasts. Clustered point mutations allowed assignment of functional borders. Single-base substitutions within a highly conserved cis element (box II/G box) defined a critical core of seven bases, 5'-ACGTGGC-3'. It is functionally equivalent to a second sequence-related element (box III), which could replace box II in an orientation-dependent manner. The activity of box II required the presence of another juxtaposed element (box I) at a defined distance. No distance requirement was observed between the two large separable promoter regions known to independently confer light-regulated expression. These data support our hypothesis that a cis-acting sequence that is present in a limited number of diversely regulated plant genes gains its functional capacity and specificity by combinatorial diversity involving flanking partner elements.
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Max-Planck-Institut für Züchtungsforschung, Abteilung Biochemie, Köln, Federal Republic of Germany.
Dangl
J L
JL
Hahlbrock
K
K
Schulze-Lefert
P
P
D000217:Acyltransferases / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D017343:Genes, Plant; D008027:Light; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes / Q000138:chemical synthesis; D010944:Plants / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D015183:Restriction Mapping
D015345:Oligonucleotide Probes; D000217:Acyltransferases; C020141:flavanone synthetase