Multicellular living organisms and unmodified parts thereof and – Method of introducing a polynucleotide molecule into or... – The polynucleotide alters fat – fatty oil – ester-type wax – or...
Patent
1995-01-09
1999-08-24
Robinson, Douglas W.
Multicellular living organisms and unmodified parts thereof and
Method of introducing a polynucleotide molecule into or...
The polynucleotide alters fat, fatty oil, ester-type wax, or...
4351723, 4353201, 435419, 536 232, 536 236, 800DIG44, A01H 500, C12N 514, C12N 1529, C12N 1552, C12N 1582
Patent
active
059426578
DESCRIPTION:
BRIEF SUMMARY
This invention relates to novel DNA constructs, plant cells containing the constructs and plants derived therefrom. In particular it involves the use of recombinant DNA technology to control, and more specifically to inhibit, the expression of two or more genes in plants.
BACKGROUND OF THE INVENTION
Plant development is a complex physiological and biochemical process requiring the co-ordinated expression of many genes. The production of new plant varieties with improved agricultural or commercial qualities can be achieved by modifying this coordinated pattern of gene expression. Such modifications have been achieved by conventional plant breeding techniques. However, the exact changes in gene expression that result in the production of the improved variety have not been readily characterised. More recently, recombinant DNA techniques have been used to modify the expression patterns of individual, specific plant genes without directly affecting the expression of other plant genes. In this way, the expression pattern of an individual gene can be either enhanced or inhibited either in the whole plant or in specific tissues or developmental stages.
The inhibition of specific individual plant genes has been achieved by the introduction into the plant of novel genes designed to express RNA homologous, in part, to the endogenous plant gene. In several cases, it has been demonstrated that expression of the target gene can be inhibited by two different strategies. These involve the introduction of specific genes designed to express either antisense or sense RNA. A typical example is the down-regulation of the gene encoding the tomato fruit cell wall enzyme, polygalacturonase, by the expression of either antisense RNA (Smith et al 1988 Nature 344, 724-726) or sense RNA (Smith et al 1990 Mol Gen Genet 224, 477-481). A further example is the down-regulation of the gene encoding chalcone synthase in petunia by either sense or antisense RNA.
The mechanisms by which the expression of a specific gene is inhibited by either antisense or sense RNA genes are not clearly understood. It has been proposed that RNA-RNA duplex molecules may be formed within the cells resulting in the inhibition of expression. However, other and perhaps different mechanisms may operate for the two strategies for down-regulation. Specific individual genes have been inhibited by greater than 99% by the two strategies independently.
SUMMARY OF THE INVENTION
According to the present invention, we provide a process for the inhibition of two or more target genes which comprises introducing into the plant a single control gene which has distinct DNA regions homologous to each of the target genes and a promoter operative in plants adapted to transcribe from such distinct regions RNA that inhibits expression of the target genes. The distinct DNA regions homologous to each of the target genes may be either sense or antisense strands. This invention can be used to generate plants with the combined benefits of down-regulation of several individual genes or families of related genes.
The present invention further provides DNA constructs containing a plant promoter positioned to transcribe an RNA strand from at least two distinct DNA regions homologous to DNA from each of at least two target genes. The distinct DNA regions may be joined sequentially or separated by a spacer region (preferably relatively short) provided such spacer region does not contain a transcription stop signal. The RNA transcribed from this single gene will contain regions homologous to the RNA transcribed from the two or more target genes.
The present invention further comprises novel cells and plants adapted to carry out the process of the invention, or which (or ancestors of which) have been transformed with the constructs of the invention.
The use of DNA constructs according to the invention offers several advantages over alternative, more complex methods of generating plants expressing homologous RNA to two or more individual target genes: eliminating the extra time and complexi
REFERENCES:
patent: 5283184 (1994-02-01), Jorgenson et al.
patent: 5387757 (1995-02-01), Bridges et al.
Walden et al. (Sep. 1995) Tibtech 13: 324-331.
Bird Colin Roger
Fray Rupert George
Grierson Donald
Schuch Wolfgang Walter
Seymour Graham Barron
Nelson Amy J.
Robinson Douglas W.
Zeneca Limited
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