Abstract
To identify new genes expressed in meristematic cells, a promoter trap insertional mutagenesis strategy was used in Arabidopsis thaliana. Transgenic line AtEM201 exhibits promoter trap GUS activity in embryos and in the regions of active cell division in the seedling, notably the apical meristems and young leaves. The tagged gene was named EXORDIUM (EXO). AtEM201 contains a single copy of the promoter trap T-DNA, located in the EXO gene promoter, resulting in a much reduced level of EXO transcription. Seedlings homozygous for the T-DNA insertion have no obvious mutant phenotype. The EXO gene, which forms part of a small gene family in Arabidopsis, is structurally related to the tobacco PHI-1 gene, which is re-activated in cultured cells following release from phosphate starvation-induced cell cycle arrest. Expression of both the EXO-GUS and the native EXO genes is downregulated by exogenous cytokinin. Expression studies using semisynchronised cells suggest that EXO mRNA is preferentially abundant during M phase of the cell cycle. Double mutant studies revealed that the exo mutation can suppress the defective root meristem phenotype of the hydra2 mutant, suggesting that EXO may be a component of a negative regulatory system for cell division.
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Claims 8
Claim · model-written summary
AtEM201 showed promoter trap activity in embryos and active division regions.
- Taxon
- Arabidopsis thaliana
Arabidopsis thalianae1 - Material
- AtEM201e0
- Organ / stage
- embryose0
- Outcome
- promoter trap GUS activitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transgenic line AtEM201 exhibits promoter trap GUS activity in embryos and in the regions of active cell division in the seedling, notably the apical meristems and young leaves.”
e1“Arabidopsis thaliana”
Claim · model-written summary
AtEM201 has one promoter trap insertion in the EXO promoter and much reduced EXO transcription.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- AtEM201e0
- Gene
- EXOe0
- Outcome
- EXO transcriptione0
- Direction
- much reducede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AtEM201 contains a single copy of the promoter trap T-DNA, located in the EXO gene promoter, resulting in a much reduced level of EXO transcription.”
e1“Arabidopsis thaliana”
Claim · model-written summary
Homozygous insertion seedlings had no obvious mutant phenotype.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Material
- Seedlings homozygous for the T-DNA insertione0
- Outcome
- no obvious mutant phenotypee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seedlings homozygous for the T-DNA insertion have no obvious mutant phenotype.”
e1“Arabidopsis thaliana”
Claim · model-written summary
EXO is part of a small gene family and structurally related to tobacco PHI-1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- EXOe0
- Outcome
- structurally related to the tobacco PHI-1 genee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The EXO gene, which forms part of a small gene family in Arabidopsis, is structurally related to the tobacco PHI-1 gene”
e1“Arabidopsis thaliana”
Claim · model-written summary
Exogenous cytokinin downregulated EXO-GUS and native EXO expression.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Treatment
- exogenous cytokinine0
- Gene
- EXOe0
- Outcome
- Expression of both the EXO-GUS and the native EXO genese0
- Direction
- downregulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of both the EXO-GUS and the native EXO genes is downregulated by exogenous cytokinin.”
e1“Arabidopsis thaliana”
Claim · model-written summary
EXO mRNA was preferentially abundant during M phase.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Organ / stage
- M phase of the cell cyclee0
- Gene
- EXOe0
- Outcome
- EXO mRNAe0
- Direction
- preferentially abundante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“EXO mRNA is preferentially abundant during M phase of the cell cycle.”
e1“Arabidopsis thaliana”
Claim · model-written summary
The exo mutation suppressed the defective root meristem phenotype of hydra2.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- exoe0
- Outcome
- defective root meristem phenotypee0
- Direction
- suppresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the exo mutation can suppress the defective root meristem phenotype of the hydra2 mutant”
e1“Arabidopsis thaliana”
Claim · model-written summary
EXO may be a component of negative regulation of cell division.
- Taxon
- Arabidopsis thalianaArabidopsis thalianae1
- Gene
- EXOe0
- Outcome
- cell divisione0
- Qualifier
- negative regulatory systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“suggesting that EXO may be a component of a negative regulatory system for cell division.”
e1“Arabidopsis thaliana”
The same questions in other papers
class · molecular: expression · Arabidopsis thaliana (thale cress)Positive and negative results
19 papers in the same direction as this paper · 23 in the opposite direction
- no effect
- positive
- positive
39 papers more in this group
See all 43 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.