Vascular expression of the grp1.8 promoter is controlled by three specific regulatory elements and one unspecific activating sequence.
The bean grp1.8 full-length promoter is specifically active in vascular tissue during normal development of tobacco. Deletion of a negative regulatory element resulted in ectopic activity of the promoter in cortical cells of hypocotyls, roots and stems. A 169 bp fragment (-205 to -36) of the grp1.8 promoter conferred vascular-specific expression to CaMV 35S minimal promoters whereas a 141 bp fragment (-205 to -64) strongly activated these minimal promoters both in vascular and cortical cells. These experiments defined a new regulatory element (VSE) that is essential for vascular-specific expression and is located between -64 and -36. The 141 bp grp1.8 promoter sequence had enhancer-like properties as it was active in both orientations. A 24 bp sequence (bp -119 to -96, corresponding to the SE1 regulatory element) enhanced expression from several minimal promoters strongly but unspecifically, whereas a 26 bp sequence (-98 to -73, corresponding to the RSE regulatory element) induced vascular-specific expression. Thus, the grp1.8 promoter is regulated by a combinatorial mechanism that can integrate the action of different, non-additively acting regulatory elements into vascular-specific expression.
Keller
B
B
Dept. of Plant Breeding, Swiss Federal Research Station for Agronomy, Zürich.
Heierli
D
D
D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D005966:Glucuronidase / Q000096:biosynthesis; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D030821:Plants, Genetically Modified; D010947:Plants, Toxic; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D012231:Rhizobium / Q000235:genetics; D014026:Nicotiana / Q000235:genetics* / Q000254:growth & development; D014170:Transformation, Genetic; D014617:Vacuoles / Q000378:metabolism*
D009838:Oligodeoxyribonucleotides; D005966:Glucuronidase