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1.
bioRxiv ; 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36711532

RESUMO

MOM1 is an Arabidopsis factor previously shown to mediate transcriptional silencing independent of major DNA methylation changes. Here we found that MOM1 localizes with sites of RNA-directed DNA methylation (RdDM). Tethering MOM1 with artificial zinc finger to unmethylated FWA promoter led to establishment of DNA methylation and FWA silencing. This process was blocked by mutations in components of the Pol V arm of the RdDM machinery, as well as by mutation of MORC6 . We found that at some endogenous RdDM sites, MOM1 is required to maintain DNA methylation and a closed chromatin state. In addition, efficient silencing of newly introduced FWA transgenes was impaired by mutation of MOM1 or mutation of genes encoding the MOM1 interacting PIAL1/2 proteins. In addition to RdDM sites, we identified a group of MOM1 peaks at active chromatin near genes that colocalized with MORC6. These findings demonstrate a multifaceted role of MOM1 in genome regulation.

2.
Nat Commun ; 11(1): 2798, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493925

RESUMO

Mediator 12 (MED12) and MED13 are components of the Mediator multi-protein complex, that facilitates the initial steps of gene transcription. Here, in an Arabidopsis mutant screen, we identify MED12 and MED13 as positive gene regulators, both of which contribute broadly to morc1 de-repressed gene expression. Both MED12 and MED13 are preferentially required for the expression of genes depleted in active chromatin marks, a chromatin signature shared with morc1 re-activated loci. We further discover that MED12 tends to interact with genes that are responsive to environmental stimuli, including light and radiation. We demonstrate that light-induced transient gene expression depends on MED12, and is accompanied by a concomitant increase in MED12 enrichment during induction. In contrast, the steady-state expression level of these genes show little dependence on MED12, suggesting that MED12 is primarily required to aid the expression of genes in transition from less-active to more active states.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Proteínas Repressoras/metabolismo , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Cromatina/metabolismo , Metilação de DNA/genética , Metilação de DNA/efeitos da radiação , Epigênese Genética/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Genes de Plantas , Genes Supressores , Loci Gênicos , Proteínas de Fluorescência Verde/metabolismo , Luz , Plantas Geneticamente Modificadas , Proteínas Repressoras/genética , Regulação para Cima/genética , Regulação para Cima/efeitos da radiação
3.
J Exp Bot ; 60(3): 1047-62, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19269998

RESUMO

Cold shock domain proteins (CSPs) are highly conserved from bacteria to higher plants and animals. Bacterial cold shock proteins function as RNA chaperones by destabilizing RNA secondary structures and promoting translation as an adaptative mechanism to low temperature stress. In animals, cold shock domain proteins exhibit broad functions related to growth and development. In order to understand better the function of CSPs in planta, detailed analyses were performed for Arabidopsis thaliana CSPs (AtCSPs) on the transcript and protein levels using an extensive series of tissue harvested throughout developmental stages within the entire life cycle of Arabidopsis. On both the transcript and protein levels, AtCSPs were enriched in shoot apical meristems and siliques. Although all AtCSPs exhibited similar expression patterns, AtCSP2 was the most abundantly expressed gene. In situ hybridization analyses were also used to confirm that AtCSP2 and AtCSP4 transcripts accumulate in developing embryos and shoot apices. AtCSPs transcripts were also induced during a controlled floral induction study. In vivo ChIP analysis confirmed that an embryo expressed MADS box transcription factor, AGL15, interacts within two AtCSP promoter regions and alters the respective patterns of AtCSP transcription. Comparative analysis of AtCSP gene expression between Landsberg and Columbia ecotypes confirmed a 1000-fold reduction of AtCSP4 gene expression in the Landsberg background. Analysis of the AtCSP4 genomic locus identified multiple polymorphisms in putative regulatory cis-elements between the two ecotypes. Collectively, these data support the hypothesis that AtCSPs are involved in the transition to flowering and silique development in Arabidopsis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/embriologia , Temperatura Baixa , Flores/embriologia , Proteínas de Ligação a RNA/metabolismo , Sementes/embriologia , Arabidopsis/genética , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/imunologia , Sequência de Bases , Imunoprecipitação da Cromatina , Flores/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genoma de Planta/genética , Soros Imunes , Hibridização In Situ , Proteínas de Domínio MADS/imunologia , Dados de Sequência Molecular , Especificidade de Órgãos , Regiões Promotoras Genéticas/genética , Estrutura Terciária de Proteína , Sementes/genética , Análise de Sequência de DNA
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