Abstract
Gene silencing with sense genes is an important method for down-regulating the expression of endogenous plant genes, but the frequency of silencing is unpredictable. Fifteen per cent of tomato plants transformed with a 35S-ACC-oxidase ( ACO 1) sense gene had reduced ACC-oxidase activity. However, 96% of plants transformed with an ACC-oxidase sense gene, containing two additional upstream inverted copies of its 5' untranslated region, exhibited reduced ACC-oxidase activity compared to wild-type plants. In the three plants chosen for analysis, there were substantially reduced amounts of both endogenous and transgenic ACO RNA, indicating that this was an example of co-suppression. Ribonuclease protection assays using probes spanning intron-exon borders showed that the reduced accumulation of endogenous ACO mRNA occurred post-transcriptionally since the abundance of unprocessed transcripts was not affected. The ACO1 transgene with the repeated 5'UTR also strongly inhibited the accumulation of RNA from the related ACO 2 gene in flowers, although there is little homology between the 5'UTRs of ACO 1 and ACO 2. These results indicate that although repeated DNA in a transgene greatly enhances the probability of gene silencing of an endogenous gene, it also involves generation of a trans -acting silencing signal produced, at least partly, from sequences external to the repeat.
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Claims 7
Claim · model-written summary
Fifteen per cent of tomato plants transformed with a 35S-ACC-oxidase (ACO1) sense gene had reduced ACC-oxidase activity.
- Taxon
- tomato
Solanum lycopersicume0 - Treatment
- transformed with a 35S-ACC-oxidase ( ACO 1) sense genee0
- Gene
- 35S-ACC-oxidase ( ACO 1) sense genee0
- Outcome
- ACC-oxidase activitye0
- Direction
- reducede0
- Value
- Fifteen per cente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fifteen per cent of tomato plants transformed with a 35S-ACC-oxidase ( ACO 1) sense gene had reduced ACC-oxidase activity”
Claim · model-written summary
96% of tomato plants transformed with an ACC-oxidase sense gene carrying two extra upstream inverted copies of its 5 prime UTR had reduced ACC-oxidase activity compared with wild-type plants.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- transformed with an ACC-oxidase sense gene, containing two additional upstream inverted copies of its 5' untranslated regione0
- Outcome
- ACC-oxidase activitye0
- Direction
- reducede0
- Value
- 96%e0
- Comparator
- wild-type plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato”
e0“96% of plants transformed with an ACC-oxidase sense gene, containing two additional upstream inverted copies of its 5' untranslated region, exhibited reduced ACC-oxidase activity compared to wild-type plants”
Claim · model-written summary
In the three analysed plants, both endogenous and transgenic ACO RNA amounts were substantially reduced, which the authors take as co-suppression.
- Taxon
- tomatoSolanum lycopersicumt0
- Outcome
- amounts of both endogenous and transgenic ACO RNAe0
- Direction
- reducede0
- Qualifier
- In the three plants chosen for analysise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato”
e0“In the three plants chosen for analysis, there were substantially reduced amounts of both endogenous and transgenic ACO RNA”
Claim · model-written summary
Reduced accumulation of endogenous ACO mRNA occurred post-transcriptionally, since unprocessed transcript abundance was not affected.
- Taxon
- tomatoSolanum lycopersicumt0
- Gene
- ACO mRNAe0
- Outcome
- reduced accumulation of endogenous ACO mRNAe0
- Qualifier
- occurred post-transcriptionallye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato”
e0“the reduced accumulation of endogenous ACO mRNA occurred post-transcriptionally since the abundance of unprocessed transcripts was not affected”
Claim · model-written summary
The ACO1 transgene with the repeated 5 prime UTR also strongly inhibited RNA accumulation from the related ACO2 gene in flowers.
- Taxon
- tomatoSolanum lycopersicumt0
- Organ / stage
- flowerse0
- Treatment
- ACO1 transgene with the repeated 5'UTRe0
- Gene
- ACO 2 genee0
- Outcome
- accumulation of RNA from the related ACO 2 genee0
- Direction
- inhibitede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato”
e0“The ACO1 transgene with the repeated 5'UTR also strongly inhibited the accumulation of RNA from the related ACO 2 gene in flowers”
Claim · model-written summary
Repeated DNA in a transgene greatly enhances the probability of silencing of an endogenous gene.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- repeated DNA in a transgenee0
- Outcome
- probability of gene silencing of an endogenous genee0
- Direction
- enhancese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato”
e0“repeated DNA in a transgene greatly enhances the probability of gene silencing of an endogenous gene”
Claim · model-written summary
Silencing by the repeated-DNA transgene involves a trans-acting silencing signal produced at least partly from sequences outside the repeat.
- Taxon
- tomatoSolanum lycopersicumt0
- Outcome
- generation of a trans -acting silencing signale0
- Qualifier
- produced, at least partly, from sequences external to the repeate0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato”
e0“it also involves generation of a trans -acting silencing signal produced, at least partly, from sequences external to the repeat”
The same questions in other papers
transgenic · molecular: expression · Solanum lycopersicum (tomato)Positive and negative results
4 papers in the same direction as this paper · 6 in the opposite direction
- positive
- no effect
- negative
7 papers more in this group
See all 11 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.