Article

Unique, shared, and redundant roles for the Arabidopsis SWI/SNF chromatin remodeling ATPases BRAHMA and SPLAYED.

Department of Biology, University of Pensylvania, Philadelphia, Penslvania 19104, USA.
The Plant Cell (impact factor: 8.99). 03/2007; 19(2):403-16. DOI:10.1105/tpc.106.048272 pp.403-16
Source: PubMed

ABSTRACT Chromatin remodeling is emerging as a central mechanism for patterning and differentiation in multicellular eukaryotes. SWI/SNF chromatin remodeling ATPases are conserved in the animal and plant kingdom and regulate transcriptional programs in response to endogenous and exogenous cues. In contrast with their metazoan orthologs, null mutants in two Arabidopsis thaliana SWI/SNF ATPases, BRAHMA (BRM) and SPLAYED (SYD), are viable, facilitating investigation of their role in the organism. Previous analyses revealed that syd and brm null mutants exhibit both similar and distinct developmental defects, yet the functional relationship between the two closely related ATPases is not understood. Another central question is whether these proteins act as general or specific transcriptional regulators. Using global expression studies, double mutant analysis, and protein interaction assays, we find overlapping functions for the two SWI/SNF ATPases. This partial diversification may have allowed expansion of the SWI/SNF ATPase regulatory repertoire, while preserving essential ancestral functions. Moreover, only a small fraction of all genes depends on SYD or BRM for expression, indicating that these SWI/SNF ATPases exhibit remarkable regulatory specificity. Our studies provide a conceptual framework for understanding the role of SWI/SNF chromatin remodeling in regulation of Arabidopsis development.

0 0
 · 
0 Bookmarks
 · 
22 Views
  • Source
    Article: Tandem bromodomains in the chromatin remodeler RSC recognize acetylated histone H3 Lys14.
    Margaret Kasten, Heather Szerlong, Hediye Erdjument-Bromage, Paul Tempst, Michel Werner, Bradley R Cairns
    [show abstract] [hide abstract]
    ABSTRACT: The coordination of chromatin remodeling with chromatin modification is a central topic in gene regulation. The yeast chromatin remodeling complex RSC bears multiple bromodomains, motifs for acetyl-lysine and histone tail interaction. Here, we identify and characterize Rsc4 and show that it bears tandem essential bromodomains. Conditional rsc4 bromodomain mutations were isolated, and were lethal in combination with gcn5Delta, whereas combinations with esa1 grew well. Replacements involving Lys14 of histone H3 (the main target of Gcn5), but not other H3 or H4 lysine residues, also conferred severe growth defects to rsc4 mutant strains. Importantly, wild-type Rsc4 bound an H3 tail peptide acetylated at Lys14, whereas a bromodomain mutant derivative did not. Loss of particular histone deacetylases suppressed rsc4 bromodomain mutations, suggesting that Rsc4 promotes gene activation. Furthermore, rsc4 mutants displayed defects in the activation of genes involved in nicotinic acid biosynthesis, cell wall integrity, and other pathways. Taken together, Rsc4 bears essential tandem bromodomains that rely on H3 Lys14 acetylation to assist RSC complex for gene activation.
    The EMBO Journal 04/2004; 23(6):1348-59. · 9.20 Impact Factor
  • Source
    Article: Integration of floral inductive signals in Arabidopsis.
    M A Blázquez, D Weigel
    [show abstract] [hide abstract]
    ABSTRACT: Flowering of Arabidopsis is regulated by a daylength-dependent pathway that accelerates flowering in long days and a daylength-independent pathway that ensures flowering in the absence of inductive conditions. These pathways are genetically separable, as there are mutations that delay flowering in long but not short days. Conversely, mutations that block synthesis of the hormone gibberellin abolish flowering in short days, but have on their own only a minor effect in long days. A third pathway, the autonomous pathway, probably acts by modulating the other two pathways. Understanding where and how these pathways are integrated is a prerequisite for understanding why similar environmental or endogenous cues can elicit opposite flowering responses in different plants. In Arabidopsis, floral induction leads ultimately to the upregulation of floral meristem-identity genes such as LEAFY, indicating that floral inductive signals are integrated upstream of LEAFY Here we show that gibberellins activate the LEAFY promoter through cis elements that are different from those that are sufficient for the daylength response, demonstrating that the LEAFY promoter integrates environmental and endogenous signals controlling flowering time.
    Nature 05/2000; 404(6780):889-92. · 36.28 Impact Factor
  • Source
    Article: A gene expression map of Arabidopsis thaliana development.
    Markus Schmid, Timothy S Davison, Stefan R Henz, Utz J Pape, Monika Demar, Martin Vingron, Bernhard Schölkopf, Detlef Weigel, Jan U Lohmann
    [show abstract] [hide abstract]
    ABSTRACT: Regulatory regions of plant genes tend to be more compact than those of animal genes, but the complement of transcription factors encoded in plant genomes is as large or larger than that found in those of animals. Plants therefore provide an opportunity to study how transcriptional programs control multicellular development. We analyzed global gene expression during development of the reference plant Arabidopsis thaliana in samples covering many stages, from embryogenesis to senescence, and diverse organs. Here, we provide a first analysis of this data set, which is part of the AtGenExpress expression atlas. We observed that the expression levels of transcription factor genes and signal transduction components are similar to those of metabolic genes. Examining the expression patterns of large gene families, we found that they are often more similar than would be expected by chance, indicating that many gene families have been co-opted for specific developmental processes.
    Nature Genetics 06/2005; 37(5):501-6. · 35.53 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

Arabidopsis thaliana SWI/SNF ATPases
 
brm null mutants exhibit
 
central mechanism
 
Chromatin
 
conceptual framework
 
distinct developmental defects
 
double mutant analysis
 
functional relationship
 
metazoan orthologs
 
multicellular eukaryotes
 
null mutants
 
plant kingdom
 
Previous analyses
 
protein interaction assays
 
proteins act
 
small fraction
 
specific transcriptional regulators
 
SWI/SNF ATPase regulatory repertoire
 
SWI/SNF chromatin
 
two SWI/SNF ATPases