Project description:The SWI/SNF chromatin remodeling complex is involved in various aspects of plant development and stress responses. In this study, we investigated the role of BRM, a core subunit of the SWI/SNF complex, in seed physiological quality in Arabidopsis thaliana. We found that brm-3 seeds exhibited enlarged size, reduced yield, increased longevity, and enhanced secondary dormancy, but no change in primary dormancy or salt tolerance. We also showed that some of these phenotypes were dependent on DOG1, a key regulator of seed dormancy, as they were reversed in the brm-3xdog1-4 double mutant. Transcriptomic and metabolomic analyses revealed that BRM and DOG1 synergisticly modulate the expression of majority genes and metabolites. In contrast some of the transcriptomic and metabolomic changes including glutathione were depended on DOG1. Moreover, we demonstrated that BRM controls secondary dormancy directly through DOG1 by binding to and remodeling its 3’ region, where an antisense promoter of DOG1 is located. Our results suggest that BRM and DOG1 cooperate to control seed physiological quality by fine-tuning the chromatin state and metabolic status of seeds. This study provides new insights into the molecular mechanisms of seed dormancy and longevity, and the interplay between chromatin remodelling at DOG1 locus.
Project description:SWI/SNF chromatin remodeling complexes control gene expression by regulating chromatin structure. However, the full subunit composition of SWI/SNF complexes in plants remains unclear. Here we show that BRAHMA Interacting Protein 1 (BRIP1) and BRIP2 in Arabidopsis thaliana are core subunits of plant SWI/SNF complexes. BRIP1 and 2 are two homolog proteins. brip1 brip2 double mutants exhibit developmental phenotypes and a transcriptome strikingly similar to those of BRAHMA (BRM) mutants. Genetic interaction tests indicated that BRIP1 and 2 act together with BRM to regulate gene expression. Furthermore, BRIP1 and 2 physically interact with BRM-containing SWI/SNF complexes, and extensively co-localize with BRM at endogenous genes. Loss-of-brip1brip2 results in decreased BRM occupancy at almost all BRM target genes and substantially reduced subunits incorporation into the BRM-containing SWI/SNF complexes. Together, our work identifies new core subunits of BRM-containing SWI/SNF complexes in plants, and uncovers the essential role of these subunits in regulating the integrity (assembly) of SWI/SNF complexes in plants.
Project description:Drosophila PBAP complex, a form of SWI/SNF class of complexes, played a important role in metamorphosis. We conducted next-generation sequencing (NGS) to analyse the expression profile in both control and Brm knockdown fly larvae.
Project description:We exogenously expressed the SWI/SNF ATPase catalytic subunits BRG1 and BRM in the lacking cell line C33A, and compared the differences with mock transfected cell at gene expression and alternative splicing level.
Project description:Drosophila PBAP complex, a form of SWI/SNF class of complexes, played a important role in metamorphosis. We conducted MNase digestion followed by next-generation sequencing (NGS) to analyse the nucleosome profile in both control and Brm knockdown fly larvae.
Project description:Arabidopsis brm plants depleted in a SWI/SNF-type ATPase BRM have decreased level of endogenous gibberellins and a phenotype that in many respects resembles the phenotype of mutants with repressed GA signaling or biosynthesis, like ga1-3. ga1-3/brm double mutant showed several additive and synergistic effects. To examine whether the phenotypic traits of brm, ga1-3 and ga1-3/brm lines are reflected at the gene expression level, we compared the expression profiles of brm, ga1-3, ga1-3/brm and wild-type plants using microarray analysis. Microarray analysis was performed on total RNA isolated from shoots of 18-d-old wt, brm, ga1-3, and ga1-3/brm seedlings. Three biological replicates were examined for each genotype. Plants were grown simultaneously under the same conditions.
Project description:Arabidopsis brm plants depleted in a SWI/SNF-type ATPase BRM have decreased level of endogenous gibberellins and a phenotype that in many respects resembles the phenotype of mutants with repressed GA signaling or biosynthesis, like ga1-3. ga1-3/brm double mutant showed several additive and synergistic effects. To examine whether the phenotypic traits of brm, ga1-3 and ga1-3/brm lines are reflected at the gene expression level, we compared the expression profiles of brm, ga1-3, ga1-3/brm and wild-type plants using microarray analysis.
Project description:Switch defective/sucrose non-fermentable chromatin remodeling complexes are multi-subunit machines that play vital roles in regulating chromatin structure and gene expression. However, how SWI/SNF complexes recognize target loci is still not fully understood. Here, we show that Arabidopsis bromodomain-containing homologous proteins, BRD1, BRD2 and BRD13, are core subunits of SWI/SNF complexes that are required for SWI/SNF genomic targeting. The three BRDs directly interact with multiple SWI/SNF subunits, including the BRAHMA (BRM) catalytic subunit. Phenotypic and transcriptome analysis of the brd1 brd2 brd13 triple mutants showed that the BRDs act in large redundancy to control developmental processes and gene expression that are also regulated by BRM. BRDs extensively co-localize with BRM on chromatin. brd1 brd2 brd13 mutation results in the reduced BRM protein levels and genome-wide targeting on chromatin. Finally, we demonstrate that the bromodomain of BRD2 is essential for genomic targeting of BRD2, highlighting the role of this reader domain in the recruitment of BRM-containing SWI/SNF complexes to target sites in plants. SWI/SNF chromatin remodeling complexes are evolutionarily conserved and is confirmed to use the energy derived from hydrolysis of ATP to alter the density or the position of nucleosomes on the DNA or the composition of histone octamer. Bromodomain, an acetylated histone interaction module, was found in chromatin remodeling factors. During the 29 Arabidopsis bromodomain-containing protein, like GCN5 and GTE4/6, their function has been reported. Here, we reported three BRM-interacting bromodomain-containing protein, BRD1, BRD2 and BRD13 are new core subunits of Arabidopsis SWI/SNF complexes. brd1/2/13 displayed a similar phenotype like brm, such as down-ward curled leaves, reduced fertility, shorter silique and root. Moreover, brm brd1/2/13 shows more serious phenotype just like brm-1. Y2H, Co-IP, RNA-seq and ChIP-seq assay reveal that BRDs interact with BRM at both protein and chromatin level. Future more, BRDs are required for BRM genome-wide occupancy and BRM might bind to chromatin via BRDs bromodomain by interacting with their BBC domain.
Project description:The SWI/SNF family of chromatin remodeling complexes is evolutionarily conserved and present in yeast, animals and plants. While the biological functions of plant SWI/SNF complexes have been studied in detail, their composition is still elusive. To clarify this picture we used protein extracts from Arabidopsis plants in vegetative phase of growth to perform a series of immunoprecipitation followed by mass spectrometry experiments, using GFP-tagged BRM ATPase as a bait. The analysis of MS data showed that the dominant form of SWI/SNF complex present in these extracts has a specific subunit composition including ARP4 and 7, SWI3C, SWP73B and BRIP2, as well as three bromodomain containing subunits, BRD1, 2 and 13. This subunit composition and the lack of the core SWI/SNF subunit BSH (SNF5/INI1) both strongly resemble the characteristics of the specific subclass of mammalian SWI/SNF complexes referred to as non-canonical BAFs, indicating that homologues of these complexes also exist in plants. We next found that depletion of the all three BRDs severely affected the assembly of this form of BRM-associated SWI/SNF complex. However, while BRD1 and BRD2 were found sufficient to allow complex formation, BRD13 was only required under BRD1/2 deficiency. The analyses of IP/MS results using BRM-GFP in different brd mutant backgrounds as well as BRD1-GFP indicate that SWI/SNF assemblies containing only one BRD isoform, BRD1 or BRD2, do exist. Furthermore, our data indicate that BRD1/2 may be necessary for the incorporation of BRIP2 subunit into the complex. Together, our results shed new light on the structural and functional diversification of SWI/SNF complexes in Arabidopsis.