Transactivation of anthocyanin biosynthetic genes following transfer of B regulatory genes into maize tissues.
The C1, B and R genes regulating the maize anthocyanin biosynthetic pathway encode tissue-specific regulatory proteins with similarities to transcriptional activators. The C1 and R regulatory genes are usually responsible for pigmentation of seed tissues, and the B-Peru allele of B, but not the B-I allele, can substitute for R function in the seed. In this study, members of the B family of regulatory genes were delivered to intact maize tissues by high velocity microprojectiles. In colorless r aleurones or embryos, the introduction of the B-Peru genomic clone or the expressed cDNAs of B-Peru or B-I resulted in anthocyanin-producing cells. Luciferase produced from the Bronze1 anthocyanin structural gene promoter was induced 100-fold when co-introduced with the expressed B-Peru or B-I cDNAs. This quantitative transactivation assay demonstrates that the proteins encoded by these two B alleles are equally able to transactivate the Bronze1 promoter. Analogous results were obtained using embryogenic callus cells. These observations suggest that one major contribution towards tissue-specific anthocyanin synthesis controlled by the various alleles of the B and R genes is the differential expression of functionally similar proteins.
Goff
S A
SA
Plant Gene Expression Center, USDA/UC Berkeley, Albany, CA 94710.
Klein
T M
TM
Roth
B A
BA
Fromm
M E
ME
Cone
K C
KC
Radicella
J P
JP
Chandler
V L
VL
D000483:Alleles; D000872:Anthocyanins / Q000378:metabolism*; D001483:Base Sequence; D002460:Cell Line; D005786:Gene Expression Regulation; D005809:Genes, Regulator; D005813:Genes, Synthetic; D005816:Genetic Complementation Test; D005822:Genetic Vectors; D008969:Molecular Sequence Data; D009029:Mosaic Viruses / Q000235:genetics; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000235:genetics; D014162:Transfection; D003313:Zea mays / Q000235:genetics*
D000872:Anthocyanins; D010940:Plant Proteins; D015534:Trans-Activators