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1.
Trends Plant Sci ; 21(7): 594-608, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26920655

RESUMO

SWI/SNF-type ATP-dependent chromatin remodeling complexes (CRCs) are evolutionarily conserved multiprotein machineries controlling DNA accessibility by regulating chromatin structure. We summarize here recent advances highlighting the role of SWI/SNF in the regulation of hormone signaling pathways and their crosstalk in Arabidopsis thaliana. We discuss the functional interdependences of SWI/SNF complexes and key elements regulating developmental and hormone signaling pathways by indicating intriguing similarities and differences in plants and humans, and summarize proposed mechanisms of SWI/SNF action on target loci. We postulate that, given their viability, several plant SWI/SNF mutants may serve as an attractive model for searching for conserved functions of SWI/SNF CRCs in hormone signaling, cell cycle control, and other regulatory pathways.


Assuntos
Arabidopsis/metabolismo , Cromatina/metabolismo , Arabidopsis/genética , Cromatina/genética , Montagem e Desmontagem da Cromatina/genética , Montagem e Desmontagem da Cromatina/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
2.
Plant Cell ; 27(7): 1889-906, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26106148

RESUMO

Arabidopsis thaliana SWP73A and SWP73B are homologs of mammalian BRAHMA-associated factors (BAF60s) that tether SWITCH/SUCROSE NONFERMENTING chromatin remodeling complexes to transcription factors of genes regulating various cell differentiation pathways. Here, we show that Arabidopsis thaliana SWP73s modulate several important developmental pathways. While undergoing normal vegetative development, swp73a mutants display reduced expression of FLOWERING LOCUS C and early flowering in short days. By contrast, swp73b mutants are characterized by retarded growth, severe defects in leaf and flower development, delayed flowering, and male sterility. MNase-Seq, transcript profiling, and ChIP-Seq studies demonstrate that SWP73B binds the promoters of ASYMMETRIC LEAVES1 and 2, KANADI1 and 3, and YABBY2, 3, and 5 genes, which regulate leaf development and show coordinately altered transcription in swp73b plants. Lack of SWP73B alters the expression patterns of APETALA1, APETALA3, and the MADS box gene AGL24, whereas other floral organ identity genes show reduced expression correlating with defects in flower development. Consistently, SWP73B binds to the promoter regions of APETALA1 and 3, SEPALLATA3, LEAFY, UNUSUAL FLORAL ORGANS, TERMINAL FLOWER1, AGAMOUS-LIKE24, and SUPPRESSOR OF CONSTANS OVEREXPRESSION1 genes, and the swp73b mutation alters nucleosome occupancy on most of these loci. In conclusion, SWP73B acts as important modulator of major developmental pathways, while SWP73A functions in flowering time control.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Flores/crescimento & desenvolvimento , Flores/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Subunidades Proteicas/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/embriologia , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Imunoprecipitação da Cromatina , Flores/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Nuclease do Micrococo/metabolismo , Mutagênese Insercional/genética , Mutação/genética , Nucleossomos/metabolismo , Folhas de Planta/genética , Regiões Promotoras Genéticas/genética , Ligação Proteica , Subunidades Proteicas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Técnicas do Sistema de Duplo-Híbrido
3.
Plant Physiol ; 163(1): 305-17, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23893173

RESUMO

Switch (SWI)/Sucrose Nonfermenting (SNF)-type chromatin-remodeling complexes (CRCs) are involved in regulation of transcription, DNA replication and repair, and cell cycle. Mutations of conserved subunits of plant CRCs severely impair growth and development; however, the underlying causes of these phenotypes are largely unknown. Here, we show that inactivation of SWI3C, the core component of Arabidopsis (Arabidopsis thaliana) SWI/SNF CRCs, interferes with normal functioning of several plant hormone pathways and alters transcriptional regulation of key genes of gibberellin (GA) biosynthesis. The resulting reduction of GA4 causes severe inhibition of hypocotyl and root elongation, which can be rescued by exogenous GA treatment. In addition, the swi3c mutation inhibits DELLA-dependent transcriptional activation of GIBBERELLIN-INSENSITIVE DWARF1 (GID1) GA receptor genes. Down-regulation of GID1a in parallel with the DELLA repressor gene REPRESSOR OF GA1-3 1 in swi3c indicates that lack of SWI3C also leads to defects in GA signaling. Together with the recent demonstration of function of SWI/SNF ATPase BRAHMA in the GA pathway, these results reveal a critical role of SWI/SNF CRC in the regulation of GA biosynthesis and signaling. Moreover, we demonstrate that SWI3C is capable of in vitro binding to, and shows in vivo bimolecular fluorescence complementation interaction in cell nuclei with, the DELLA proteins RGA-LIKE2 and RGA-LIKE3, which affect transcriptional activation of GID1 and GA3ox (GIBBERELLIN 3-OXIDASE) genes controlling GA perception and biosynthesis, respectively. Furthermore, we show that SWI3C also interacts with the O-GlcNAc (O-linked N-acetylglucosamine) transferase SPINDLY required for proper functioning of DELLAs and acts hypostatically to (SPINDLY) in the GA response pathway. These findings suggest that DELLA-mediated effects in GA signaling as well as their role as a hub in hormonal cross talk may be, at least in part, dependent on their direct physical interaction with complexes responsible for modulation of chromatin structure.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/efeitos dos fármacos , Proteínas Cromossômicas não Histona/fisiologia , Giberelinas/farmacologia , Reguladores de Crescimento de Plantas/farmacologia , Transdução de Sinais/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Núcleo Celular/metabolismo , Montagem e Desmontagem da Cromatina , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Regulação da Expressão Gênica de Plantas
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