Separate cis sequences and trans factors direct metabolic and developmental regulation of a potato tuber storage protein gene.
The expression of genes encoding patatin, a major tuber protein, is highly tissue-specific but is also modulated by exogenous sucrose. The patterns of transcription observed in potato plants could be due to mechanisms conferring tuber-specificity or they could reflect the concentrations of sucrose found in different tissues. To distinguish between these possibilities, a detailed examination was made of the function of a region of the promoter previously implicated in conferring tissue-specific and sucrose-inducible expression. Internal deletions of this region revealed three separate functional domains regulating expression. The B repeat region acted as a positive activator of transcription in the tuber and was also responsible for a degree of sucrose-inducibility. The distal region of the A repeat repressed transcription in leaf and tuber tissue, while the proximal region of the A repeat was able to confer sucrose-responsiveness. Each of these regions specifically bound nuclear proteins which may be putative transcription factors involved in conferring these responses. The region found to confer sucrose-inducible expression was conserved among some other genes that are also regulated by exogenous sucrose.
Grierson
C
C
Molecular Genetics Department, John Innes Centre, Norwich, UK.
Du
J S
JS
de Torres Zabala
M
M
Beggs
K
K
Smith
C
C
Holdsworth
M
M
Bevan
M
M
D001483:Base Sequence; D002265:Carboxylic Ester Hydrolases; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics*; D017343:Genes, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D012091:Repetitive Sequences, Nucleic Acid / Q000502:physiology; D017384:Sequence Deletion / Q000235:genetics; D011198:Solanum tuberosum / Q000235:genetics*; D013395:Sucrose / Q000502:physiology; D015533:Transcriptional Activation / Q000235:genetics
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; C043222:patatin protein, Solanum tuberosum; D013395:Sucrose; D004247:DNA; D002265:Carboxylic Ester Hydrolases