Col-0 and WEE1KO (wee1-1 and wee1-2) were germinated on control medium on a nylon mesh and transferred 5 days after germination to control medium. Samples were harvested at three different time points after transfer: 0 h, 5 h, and 24 h. All sampling points were performed in four independent experiments for Col-0, two independent experiments for wee1-1 and two independent experiments for wee1-2. For each time point in each experiment ᄆ50 root tips were collected and frozen in liquid nitrogen. RNA was extracted from root tissue with TriZol reagent (Invitrogen) and purified with RNneasy kit (Qiagen). The RNA of two independent experiments for Col-0 and WEE1KO were subsequently pooled and used for microarray analysis.
The Arabidopsis thaliana checkpoint kinase WEE1 protects against premature vascular differentiation during replication stress
Age, Specimen part, Time
View SamplesCol-0 and WEE1KO (wee1-1 and wee1-2) were germinated on control medium on a nylon mesh and transferred 5 days after germination to medium supplemented with 2 mM HU. Samples were harvested at three different time points after transfer: 0 h, 5 h, and 24 h. All sampling points were performed in four independent experiments for Col-0, two independent experiments for wee1-1 and 2 independent experiments for wee1-2. For each time point in each experiment ᄆ50 root tips were collected and frozen in liquid nitrogen. RNA was extracted from root tissue with TriZol reagent (Invitrogen) and purified with RNneasy kit (Qiagen). The RNA of two independent experiments for Col-0 and WEE1KO were subsequently pooled and used for<br></br>microarray analysis.
The Arabidopsis thaliana checkpoint kinase WEE1 protects against premature vascular differentiation during replication stress
Age, Specimen part, Time
View SamplesTranscriptome changes 1h or 4h following DELLA stabilisation in microdissected fully proliferating Arabidopsis leaves
Gibberellins and DELLAs: central nodes in growth regulatory networks.
Specimen part, Treatment, Time
View SamplesTranscriptome changes in 35S::KLU shoots at stage 1.03 compared to wild-type (WT) Col-0 shoots
No associated publication
Specimen part
View SamplesThe final size of plant organs such as leaves is tightly controlled by environmental and genetic factors that must spatially and temporally coordinate cell expansion and cell cycle activity. However this regulation of organ growth is still poorly understood. The aim of this study is to gain more insight in the genetic control of leaf size in Arabidopsis by performing a comparative analysis of transgenic lines that produce larger leaves under standardized environmental conditions. To this end, we selected five genes, belonging to different functional classes, that all positively affect leaf size when over-expressed: AVP1, GRF5, JAW, BRI1 and GA20OX1. We show that the increase in leaf area in these lines depends on leaf position and growth conditions and that all five lines affect leaf size differently. However, in all cases an increase in cell number is, entirely or predominantly, responsible for the leaf size enlargement. By means of analyses of hormone levels, transcriptome and metabolome we provide deeper insight in the molecular basis of the growth phenotype for the individual lines. A comparative analysis between them indicates that enhanced organ growth is governed by different, seemingly independent pathways. The analysis of transgenic lines simultaneously over-expressing two growth-enhancing genes further supports the concept that multiple pathways independently converge on organ size control in Arabidopsis.
Increased leaf size: different means to an end.
Specimen part
View SamplesThe goal of this study is to identify co-expressed genes downstream of Atonal and Senseless. These gene lists are used as candidate target genes (technically: as foreground sets) in computational predictions of cis-regulatory elements using the cisTargetX method (http://med.kuleuven.be/cme-mg/lng/cisTargetX). Together, the gene expression results and cis-regulatory predictions, yield a gene regulatory network underlying the early events in retinal differentiation. Predicted cis-regulatory interactions have been validated extensively in vivo using enhancer reporter assays and genetic perturbations.
No associated publication
Specimen part
View SamplesThe number of cells in an organ is a major factor for the determination of organ size. However, genetic basis of cell number determination is not well understood. Three grandifolia-D (gra-D) mutants of Arabidopsis thaliana developed huge leaves containing two- to three-fold increased number of cells of the wild type. Tiling array and microarray analysis of gra-D mutants suggested that genes found in a lower part of chromosome 4 were upregulated, suggesting the occurrence of segmental chromosomal duplications in the gra-D mutants. These region contain positive regulators of cell proliferation such as AINTEGUMENTA (ANT) and cyclin genes such as CYCD3;1.
Impact of segmental chromosomal duplications on leaf size in the grandifolia-D mutants of Arabidopsis thaliana.
Specimen part
View SamplesThe number of cells in an organ is a major factor for the determination of organ size. However, genetic basis of cell number determination is not well understood. Three grandifolia-D (gra-D) mutants of Arabidopsis thaliana developed huge leaves containing two- to three-fold increased number of cells of the wild type. Tiling array and microarray analysis of gra-D mutants suggested that genes found in a lower part of chromosome 4 were upregulated, suggesting the occurrence of segmental chromosomal duplications in the gra-D mutants. These region contain positive regulators of cell proliferation such as AINTEGUMENTA (ANT) and cyclin genes such as CYCD3;1.
Impact of segmental chromosomal duplications on leaf size in the grandifolia-D mutants of Arabidopsis thaliana.
Specimen part
View SamplesThe final size of plant organs such as leaves is tightly controlled by environmental and genetic factors that must spatially and temporally coordinate cell expansion and cell cycle activity. However this regulation of organ growth is still poorly understood. The aim of this study is to gain more insight in the genetic control of leaf size in Arabidopsis by performing a comparative analysis of transgenic lines that produce larger leaves under standardized environmental conditions. To this end, we selected five genes, belonging to different functional classes, that all positively affect leaf size when over-expressed: AVP1, GRF5, JAW, BRI1 and GA20OX1. We show that the increase in leaf area in these lines depends on leaf position and growth conditions and that all five lines affect leaf size differently. However, in all cases an increase in cell number is, entirely or predominantly, responsible for the leaf size enlargement. By means of analyses of hormone levels, transcriptome and metabolome we provide deeper insight in the molecular basis of the growth phenotype for the individual lines. A comparative analysis between them indicates that enhanced organ growth is governed by different, seemingly independent pathways. The analysis of transgenic lines simultaneously over-expressing two growth-enhancing genes further supports the concept that multiple pathways independently converge on organ size control in Arabidopsis.
Increased leaf size: different means to an end.
Specimen part
View SamplesSHORT-ROOT (SHR) and SCARECROW (SCR) are required for stem cell maintenance in the Arabidopsis thaliana root meristem, ensuring its indeterminate growth. Mutation of SHR and SCR genes results in disorganization of the quiescent center and loss of stem cell activity, resulting in the cessation of root growth. This manuscript reports on the role of SHR and SCR in the development of leaves, which, in contrast to the root, have a determinate growth pattern and lack a persistent stem-cell niche. Our results demonstrate that inhibition of leaf growth in shr and scr mutants is not a secondary effect of the compromised root development, but is caused by a direct effect on cell division in the leaves: a reduced cell division rate and early exit of proliferation phase. Consistent with the observed cell division phenotype, the expression of SHR and SCR genes in leaves is closely associated with cell division activity in most cell types. The increased cell cycle duration is due to a prolonged S-phase duration, which is mediated by up-regulation of cell cycle inhibitors known to restrain the activity of the transcription factor, E2Fa. Therefore, we conclude that, in contrast to their specific role in cortex/endodermis differentiation and stem cell maintenance in the root, SHR and SCR primarily function as general regulators of cell proliferation in leaves.
No associated publication
Specimen part
View Samples