ISSN:
1617-4623
Keywords:
Chlorophyll a/b binding protein genes
;
Divergent promoters
;
Coordinate expression
;
Between-transformant variability
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary We examined the divergent Cab22R and Cab22L genes of petunia as a coupled photosynthetic promoter casstte for simultaneously directing high level expression of two foreign genes in a coordinated and tissue specific manner in transgenic plants. Primer extension assays with gene specific primers on petunia leaf RNA indicated that abundant and coordinated mRNA expression occurs for the two Cab22 divergent transcription units in a tissue specific and light regulated fashion. The expression characteristics of the intact Cab22 genes can be maintained in transgenic tobacco plants, but are influenced by the site of insertion into the Agrobacterium T-DNA binary vector. Thus, the expression levels of genes introduced near the T-DNA left border varied coordinatedly among independently transformed plants and remained completely light inducible and tissue specific. In contrast, each of these transcription properties was significantly disrupted by the insertion of the genes into the right section of the binary vector, between a selectable NPTII gene and the T-DNA octopine synthase (Ocs) cis-acting promoter element. Gene transfer experiments with chimeric gene constructs have shown that both the quantitative and qualitative expression properties of the Cab22 genes can be conferred to foreign protein coding genes via fusion to the Cab22 leader and upstream sequences. The use of this divergent promoter as a cassette to express foreign genes in plants in a coordinated fashion and the possible influences of differential mRNA stabilities and transcription rates between intact and chimeric genes in transgenic plants are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00425708
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