Project description:A pilot experiment for an RNA-seq dataset (SRP003234). This experiment compares AP1 domain-specific translating RNA with total flower translating mRNA. Two-condition experiment, AP1 flower domains vs. whole flower at flower stage 4.
Project description:A pilot experiment for an RNA-seq dataset (SRP003234). This experiment compares AP1 domain-specific translating RNA with total flower translating mRNA.
Project description:This experiment describes gene expression during early Arabidopsis flower development. We used a 35S:AP1-GR ap1 cal line to induce synchronized flower development by specifically activating the AP1-GR fusion protein in ap1 cal inflorescence-like meristems through dexamethasone treatment. Tissue samples were collected immediately after the treatment, as well as at one-day intervals for the following five days. The expression profiles of the individual samples were then analyzed by gene expression profiling using whole-genome microarrays (Operon). Keywords: time course
Project description:Gene expression is controlled by the complex interaction of transcription factors binding to promoters and other regulatory DNA elements. One common characteristic of the genomic regions associated with regulatory proteins is a pronounced sensitivity to DNase I digestion. We reported genome-wide high resolution maps of DNase I hypersensitive (DH) sites from both seedling and flower tissues of Arabidopsis from the Columbia (Col) ecotype and the corresponding ddm1 (deficient in DNA methylation 1) mutant. We identified 38,290, 41,193, 38,313, and 38,153 DH sites in leaf (Col), flower (Col), ddm1 leaf, and ddm1 flower tissues, respectively. Approximately 45% of the DH sites in all tissue types were located within 1 kb of a transcription start site (TSS), which represents a putative promoter region. Pairwise comparisons of the DH sites derived from different tissue types revealed DH sites specific to each tissue. DH sites are significantly associated with long non-coding RNAs (lncRNAs) and conserved non-coding sequences (CNSs). The binding sites of MADS-domain transcription factors AP1 and SEP3 are highly correlated with DH sites.
Project description:Plants have evolved a unique and conserved developmental program that enables the conversion of leaves into floral organs. Elegant genetic and molecular work has identified key regulators of floral meristem identity. However, further understanding of flower meristem specification has been hampered by redundancy and by pleiotropic effects. The KNOXI gene STM transcription factor is a well-characterized regulator of shoot apical meristem maintenance. stm loss-of-function mutants arrest shortly after germination, and therefore the knowledge on later roles of STM, including flower development, is limited. Here, we uncover a role for STM in the specification of flower meristem identity. Silencing STM in the AP1 expression domain in the ap1-4 mutant background resulted in a complete leafy-like flower phenotype and an intermediate stm-2 allele enhanced the floral meristem identity phenotype of ap1-4. Transcriptional profiling of STM perturbation suggested that STM activity affects multiple meristem identity and flower transition genes, among them the F-Box gene UFO. In agreement, stm-2 enhanced the ufo-2 floral meristem fate phenotype, and ectopic UFO expression rescued the leafy flowers in genetic backgrounds with compromised AP1 and STM activities. This work suggests a molecular mechanism that underlies the activity of STM in the specification of flower meristem identity.
Project description:Plant inflorescence-to-floral phase transition is an important developmental stage, in which floral cell identities and many traits of reproductive organs are determined. Two MADS-domain transcription factors, APETALA1 (AP1) and CAULIFLOWER (CAL), have been known as master regulators controlling the early stage of the phase transition in Arabidopsis. In plants with loss-of-function alleles of ap1 and cal double mutations, flower development is heavily delayed at the flower initiation stage and accumulate a large number of inflorescence-like meristem cells compared to wild-type plants, resulting in a cauliflower-like phenotype. To facilitate investigation on molecular mechanisms during inflorescence-to-floral phase transition, an inducible system of synchronized floral development has been developed, in which ap1,cal inflorescence-like meristem cells express a fusion protein of AP1 and the hormone-binding domain of the rat glucocorticoid receptor (GR) driven by 35S constitutive promoter. When inflorescences of 35S:AP1-GR ap1,cal plants are treated by steroid hormone dexamethasone as the activator to allow the AP1-GR fusion protein translocate into nucleus, inflorescence-to-floral phase transition is triggered and plants start to produce hundreds of relatively synchronized floral buds. To explore molecular basis at early stage of flower development in Arabidopsis, we used the inducible system of synchronized floral development (35S:AP1-GR ap1,cal) to profile transcriptome change of meristem cells during inflorescence-to-floral phase transition by strand-specific RNA-sequencing.
Project description:Gene expression is controlled by the complex interaction of transcription factors binding to promoters and other regulatory DNA elements. One common characteristic of the genomic regions associated with regulatory proteins is a pronounced sensitivity to DNase I digestion. We reported genome-wide high resolution maps of DNase I hypersensitive (DH) sites from both seedling and flower tissues of Arabidopsis from the Columbia (Col) ecotype and the corresponding ddm1 (deficient in DNA methylation 1) mutant. We identified 38,290, 41,193, 38,313, and 38,153 DH sites in leaf (Col), flower (Col), ddm1 leaf, and ddm1 flower tissues, respectively. Approximately 45% of the DH sites in all tissue types were located within 1 kb of a transcription start site (TSS), which represents a putative promoter region. Pairwise comparisons of the DH sites derived from different tissue types revealed DH sites specific to each tissue. DH sites are significantly associated with long non-coding RNAs (lncRNAs) and conserved non-coding sequences (CNSs). The binding sites of MADS-domain transcription factors AP1 and SEP3 are highly correlated with DH sites. To map the DH sites in A. thaliana, we constructed a total of five DNase-seq libraries using leaf and flower tissues from the Columbia (Col) ecotype and a ddm1 (deficient in DNA methylation 1) mutant of Columbia. These libraries were sequenced using the Illumina Genome Analyzer. We obtained a total of 190 million (M) sequence reads from these libraries. Approximately 114 M reads had a single sequence match in the A. thaliana genome
Project description:The MADS-domain transcription factor APETALA1 (AP1) is a key regulator of Arabidopsis flower development. To understand the molecular mechanisms underlying AP1 function, we identified its target genes during floral initiation using a combination of gene expression profiling and genome-wide binding studies. Many of its targets encode transcriptional regulators, including known floral repressors. The latter genes are down-regulated by AP1, suggesting that it initiates floral development by abrogating the inhibitory effects of these genes. While AP1 acts predominantly as a transcriptional repressor during the earliest stages of flower development, regulatory genes known to be required for floral organ formation were found to be activated by AP1 at more advanced stages, indicating a dynamic mode of action. Our results further imply that AP1 orchestrates floral initiation by integrating growth, patterning and hormonal pathways. We used the AP1-GR system to conduct chromatin immunoprecipitation experiments with AP1-specific antibodies followed by deep-sequencing (ChIP-Seq) in order to determine AP1 binding sites on a genome-wide scale. Samples were generated from tissue in which the AP1-GR protein was induced for 2h using a single treatment of 1 uM DEX to the shoot apex. As control, we performed ChIP experiments using the same antibody on uninduced tissue. Experiments were done in two biological replicates.
Project description:The aim of this study was to analyze the impact of autotetraploidy on gene expression in Arabidopsis thaliana by comparing diploid versus tetraploid transcriptomes. In particular, this included the comparison of the transcriptome of different tetraploid A. thaliana ecotypes (Col-0 vs. Ler-0). The study was extended to address further aspects. One was the comparison of the transcriptomes in subsequent generations. This intended to obtain information on the genome wide stability of autotetraploid gene expression. Another line of work compared the transcriptomes of different diploid vs. tetraploid tissues. This aimed to investigate whether particular gene groups are specifically affected during the development of A. thaliana autotetraploids. Samples 1-8: Arabidopsis thaliana Col-0 tetraploid transcriptome. Transcriptional profiling and comparison of diploid vs. tetraploid Col-0 seedlings. The experiment was carried out with pedigree of independently generated and assessed tetraploid Col-0 lines. Samples 9-12: Arabidopsis thaliana Ler-0 tetraploid transcriptome. Transcriptional profiling and comparison of diploid vs. tetraploid Ler-0 seedlings. The experiment was carried out with pedigree of independently generated and assessed tetraploid Ler-0 lines. Samples 13-24: Arabidopsis thaliana Col-0 tetraploid transcriptome. Transcriptional profiling and comparison of diploid vs. tetraploid Col-0 leaves (6th - 8th). The experiment was carried out with pedigree of independently generated and assessed tetraploid Col-0 lines. Samples 25-32: Arabidopsis thaliana Ler-0 tetraploid transcriptome. Transcriptional profiling and comparison of diploid vs. tetraploid Ler-0 leaves (6th - 8th). The experiment was carried out with pedigree of independently generated and assessed tetraploid Ler-0 lines. Samples 33-36: Arabidopsis thaliana Ler-0 tetraploid transcriptome. Transcriptional profiling and comparison of tetraploid vs. tetraploid Ler-0 seedlings from the second (F2) and third (F3) generation after induction, respectively. The experiment was carried out with pedigree of independently generated and assessed tetraploid Ler-0 lines. Samples 37-40: Arabidopsis thaliana Col-0 tetraploid transcriptome. Transcriptional profiling and comparison of tetraploid vs. tetraploid Col-0 seedlings from the second (F2) and third (F3) generation after induction, respectively. The experiment was carried out with pedigree of independently generated and assessed tetraploid Col-0 lines. Samples 41-44: Arabidopsis thaliana Col-0/Ler-0 diploid transcriptome. Transcriptional profiling and comparison of diploid Col-0 vs. diploid Ler-0 seedlings. The experiment was carried out with pedigree of esrablished lines. Samples 45-48: Arabidopsis thaliana Col-0/Ler-0 tetraploid transcriptome. Transcriptional profiling and comparison of tetraploid Col-0 vs tetraploid Ler-0 seedlings. The experiment was carried out with pedigree of independently generated and assessed tetraploid Col-0 and Ler-0 lines.