Orchestration of Floral Initiation by APETALA1
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE20176 | GEO | 2010/04/02
SECONDARY ACCESSION(S): PRJNA125645
REPOSITORIES: GEO
Similar Datasets
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.
2010-04-02 | E-GEOD-20176 | biostudies-arrayexpress
Project description:The transcription factors LEAFY (LFY) and APETALA1 (AP1), together with the AP1 paralog CAULIFLOWER (CAL), control the onset of flower development in a partially redundant manner. This redundancy is thought to be mediated, at least in part, through the regulation of a shared set of target genes. However, whether these genes are independently or cooperatively regulated by LFY and AP1/CAL, is currently unknown. To better understand the regulatory relationship between LFY and AP1/CAL during floral initiation, we monitored the activity of LFY in the absence of AP1/CAL function. We found that the regulation of several known LFY target genes is unaffected by AP1/CAL perturbation, while others appear to require AP1/CAL activity. Furthermore, we obtained evidence that LFY and AP1/CAL control the expression of some genes in an antagonistic manner. Notably, these include key regulators of floral initiation such TERMINAL FLOWER1 (TFL1), which had been previously reported to be directly repressed by both LFY and AP1. We show here that TFL1 expression is suppressed by AP1 but promoted by LFY. We further demonstrate that LFY has an inhibitory effect on flower formation in the absence of AP1/CAL activity. We propose that LFY and AP1/CAL may act as part of an incoherent feed-forward loop to control the establishment of a stable developmental program for the formation of flowers.
2017-04-28 | GSE96806 | GEO
Project description:The transcription factors LEAFY (LFY) and APETALA1 (AP1)_together with the AP1 paralog CAULIFLOWER (CAL)_control the onRep_of flower development in a partially redundant manner. This redundancy is thought to be mediated_at least in part_through the regulation of a shared Rep_of target genes. However_whether these genes are independently or cooperatively regulated by LFY and AP1/CAL_is currently unknown. To better understand the regulatory relationship between LFY and AP1/CAL during floral initiation_we monitored the activity of LFY in the absence of AP1/CAL function. We found that the regulation of several known LFY target genes is unaffected by AP1/CAL perturbation_while others appear to require AP1/CAL activity. Furthermore_we obtained evidence that LFY and AP1/CAL control the expression of some genes in an antagonistic manner. Notably_these include key regulators of floral initiation such TERMINAL FLOWER1 (TFL1)_which had been previously reported to be directly repressed by both LFY and AP1. We show here that TFL1 expression is suppressed by AP1 but promoted by LFY. We further demonstrate that LFY has an inhibitory effect on flower formation in the absence of AP1/CAL activity. We propose that LFY and AP1/CAL may act as part of an incoherent feed-forward loop to control the establishment of a stable developmental program for the formation of flowers.
2017-04-28 | GSE96799 | GEO
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.
2018-12-01 | GSE59677 | GEO
Project description:This SuperSeries is composed of the following subset Series: GSE20139: Ath_Agilent_v1_Riechmann array expression profile AP1-GR ap1cal inflorescences - time series (hours) GSE20182: Meyerowitz Lab Arabidopsis Operon Array v4 - 4200A scanner - AP1-GR ap1cal inflorescences - time series (hours) GSE20183: Meyerowitz Lab Arabidopsis Operon Array v4 - 4000B scanner - AP1-GR ap1cal inflorescences - time series (hours) Refer to individual Series
2010-04-02 | E-GEOD-20184 | biostudies-arrayexpress
Project description:Comparion of gene expression profiles of wild-type and apetala1 inflorescences The gene expression profile of inflorescences of the floral homeotic mutant apetala1 was compared to wild-type inflorescences (Ler) using a whole-genome oligonucleotide array (Agilent, custom-commercial). Experiment was performed in triplicate.
2010-04-02 | GSE20138 | GEO
Project description:Although the pattern of lateral organ formation from apical meristems establishes species-specific plant architecture, the positional information that confers cell fate to cells as they transit to the meristem flanks where they differentiate, remains largely unknown. We have combined fluorescence-activated cell sorting and RNA-seq to characterise the cell-type-specific transcriptome at the earliest developmental time-point of lateral organ formation using DORNRÖSCHEN-LIKE::GFP to mark founder-cell populations at the periphery of the inflorescence meristem (IM) in apetala1 cauliflower double mutants, which overproliferate IMs. Within these founder-cells, floral primordium identity genes are upregulated and stem-cell identity markers are downregulated. The transcriptional network of differentially expressed genes supports the hypothesis that lateral organ founder-cell specification involves the creation of polarity from the centre to the periphery of the IM and the establishment of a boundary from surrounding cells, consistent with bract initiation. In contrast to the established paradigm that sites of auxin response maxima pre-pattern lateral organ initiation in the IM, only subtle transcriptional reprogramming within the global auxin network was observed, suggesting that auxin response might play a minor role in the earliest stages of lateral floral initiation.
2016-11-03 | GSE81401 | GEO
Project description:Comparion of gene expression profiles of wild-type and apetala1 inflorescences The gene expression profile of inflorescences of the floral homeotic mutant apetala1 was compared to wild-type inflorescences (Ler) using a whole-genome oligonucleotide array (Agilent, custom-commercial). Experiment was performed in triplicate. This series contains the data for three replicate experiments performed with three sets of independent samples. The combined ratio data results are available as a supplementary file on the Series record.
2010-04-02 | E-GEOD-20138 | biostudies-arrayexpress
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.
2018-05-04 | GSE113894 | GEO
Project description:Pineapple (Ananas comosus var. comosus) and ornamental bromeliads are commercially induced to flower by treatment with ethylene or its analogs. The apex is transformed from a vegetative to a floral meristem and shows morphological changes in 8 to 10 days, with flowers developing 8 to 10 weeks later. During eight sampling stages ranging from 6 hours to 8 days after treatment, 7,961 genes were found to exhibit differential expression (DEG) after the application of ethylene. In the first 3 days after treatment, there was little change in ethylene synthesis or in the early stages of the ethylene response. Subsequently, three ethylene response transcription factors (ERTF) were up-regulated and the potential gene targets were predicted to be the positive flowering regulator CONSTANS (CO), a WUSCHEL gene, two APETALA1/FRUTFULL (AP1/FUL) genes, an epidermal patterning gene and a jasmonic acid synthesis gene. We confirm that pineapple has lost the flowering repressor FLOWERING LOCUS C. At the initial stages, the SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) was not significantly involved in this transition. Another WUSCHEL gene and a PHD homeobox transcription factor, though not apparent direct targets of ERTF, were up-regulated within a day of treatment, their predicted targets being the up-regulated CO, auxin response factors, SQUAMOSA, and histone H3 genes with suppression of abscisic acid response genes. The FLOWERING LOCUS T (FT), TERMINAL FLOWER (TFL), AGAMOUS-like APETELAR (AP2) and SEPETALA (SEP) increased rapidly within 2 to 3 days after ethylene treatment. Two FT genes were up-regulated in the apex and not the leaf bases after treatment, suggesting that transport did not occur. These results indicated that the ethylene response in pineapple and possibly most bromeliads acts directly to promote the vegetative to flower transition via APETALA1/FRUITFULL (AP1/FUL) and its interaction with SPL, FT, TFL, SEP and AP2.
2023-11-22 | GSE241286 | GEO