Disruption of the plant gene MOM releases transcriptional silencing of methylated genes

Amedeo, Paolo; Habu, Yoshiki; Afsar, Karin; Scheid, Ortrun Mittelsten; Paszkowski, Jerzy

doi:10.1038/35012108

Cited by 248 publications

(271 citation statements)

References 30 publications

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“…Given that DNA methylation has not been reported at the FLC locus, it appears that DNA methylation is not a requirement for the recruitment of FPA and possibly other AP components. It is worth noting that the activation of methylated loci without a reduction in DNA methylation is not unprecedented; morpheus' molecule1 mutations lead to the activation of methylated loci without affecting DNA methylation (Amedeo et al, 2000). Thus, processes downstream of DNA methylation are required for transcriptional silencing, and the AP may play a role in this process.…”

Section: Discussionmentioning

confidence: 99%

Functional Redundancy and New Roles for Genes of the Autonomous Floral-Promotion Pathway

Veley

Michaels

2008

Plant Physiology

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The early-flowering habit of rapid-cycling accessions of Arabidopsis (Arabidopsis thaliana) is, in part, due to the genes of the autonomous floral-promotion pathway (AP). The AP promotes flowering by repressing expression of the floral inhibitor FLOWERING LOCUS C (FLC). AP mutants are therefore late flowering due to elevated levels of FLC, and this late-flowering phenotype is eliminated by loss-of-function mutations in FLC. To further investigate the role of the AP, we created a series of double mutants. In contrast to the phenotypes of single mutants, which are largely limited to delayed flowering, a subset of AP double mutants show a range of defects in growth and development. These phenotypes include reduced size, chlorophyll content, growth rate, and fertility. Unlike the effects of the AP on flowering time, these phenotypes are FLC independent. Recent work has also shown that two AP genes, FCA and FPA, are required for the repression and, in some cases, proper DNA methylation of two transposons. We show that similar effects are seen for all AP genes tested. Microarray analysis of gene expression in AP single and double mutants, however, suggests that the AP is not likely to play a broad role in the repression of gene expression through DNA methylation: very few of the genes that have been reported to be up-regulated in DNA methylation mutants are misexpressed in AP mutants. Together, these data indicate that the genes of the AP play important and sometimes functionally redundant roles in aspects of development in addition to flowering time.A fundamental question in biology is how differentiating cells make decisions between alternative fates. The change from vegetative to reproductive development in Arabidopsis (Arabidopsis thaliana) is an attractive model for studying the factors that regulate such developmental transitions. Early in the life cycle, the undifferentiated stem cells of the shoot apical meristem give rise to organ primordia that will produce the vegetative portions of the plant (e.g. leaves). Later, the shoot apical meristem switches to producing primordia that will form the reproductive organs (e.g. flowers). Proper timing of this transition is critical for successful reproduction. Therefore, plants have evolved mechanisms to regulate flowering in response to both endogenous and environmental factors (Boss et al., 2004). These mechanisms help to ensure that plants flower at a suitable time in their development and a favorable time of year.

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Section: Discussionmentioning

confidence: 99%

Functional Redundancy and New Roles for Genes of the Autonomous Floral-Promotion Pathway

Veley

Michaels

2008

Plant Physiology

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“…Similarly, Lembo et al (36) recently reported that MBDin, a regulatory factor of MBD2, reversed MBD2-mediated transcriptional repression from a methylated promoter by binding with the COOHterminal region of MBD2. Another example of antisilencing without DNA demethylation has been shown in plants (37). MOM is an Arabidopsis gene that has been found to be important in maintaining gene silencing in a methylation-independent fashion.…”

Section: Discussionmentioning

confidence: 99%

Halogenated Thymidine Analogues Restore the Expression of Silenced Genes without Demethylation

et al. 2005

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Transcriptional silencing of tumor suppressor genes by aberrant DNA methylation is a characteristic frequently observed in cancer cells. Therefore, reversing this process is a therapeutic target against cancer. In this study, we established a screening system for silencing inhibitors with cell lines transfected by a retroviral vector containing a luciferase gene.More than 100 nucleosides were tested for antisilencing activity with a selected clone in which the silenced expression of luciferase could be recovered by 5-aza-2V -deoxycytidine. A group of halogenated thymidine analogues was found to reactivate transcription of not only the reporter retrovirus vector but also endogenous glutathione-S-transferase 1 gene, without influence to DNA hypermethylation. Gel mobility shift assay showed that 5-bromo-2V-deoxyuridine (BrdUrd) or 5-iodo-2V-deoxyuridine incorporation did not affect the binding of the methyl-CpG binding protein motif to methylated DNA. Finally, in the retroviral promoter, BrdUrd treatment increased the acetylated histone H3 level and decreased methylation of histone H3 Lys 9 in accordance with recovered transcription. This study shows that halogenated thymidines have an antisilencing effect without changing DNA methylation status by interfering with step(s) between DNA methylation and histone acetylation. (Cancer Res 2005; 65(15): 6927-33)

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“…Like DDM1, the MORPHEUS MOLECULE (MOM) gene also encodes a SWI/SNF-like protein that, similar to DDM1, can also release transcriptional gene silencing. However, in contrast to ddm1 mutants in mom mutants, no changes in DNA methylation have been observed (Amedeo et al 2000). To address the question of whether the mom mu- tation could also modify PHE1 expression in an mea mutant background, we analyzed PHE1 mRNA levels by real-time PCR in mea/MEA; mom/mom double-mutant plants (F3 generation) during different stages of seed development.…”

Section: Phe1ϻgus Is Expressed In the Absence Of Fertilization In Fiementioning

confidence: 99%

ThePolycomb-group protein MEDEA regulates seed development by controlling expression of the MADS-box genePHERES1

Köhler¹,

Hennig²,

Spillane³

et al. 2003

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The life cycle of higher plants alternates between a haploid gametophytic generation and a diploid sporophytic generation. The female and male gametes formed during the gametophytic phase fuse during fertilization to generate the sporophytic phase of the life cycle. Most sexually reproducing diploid plants undergo double fertilization, during which the egg cell and the homodiploid central cell are each fertilized by a sperm cell and give rise to the embryo and the triploid endosperm, respectively (Grossniklaus and Schneitz 1998).In analogy to the Greek myth in which the priestess Medea killed her children Pheres and Meidos (Euripides 431 BC; Wolf 1996), a maternal effect mutant identified in a screen for gametophytic mutants in Arabidopsis thaliana was named medea (mea; . Additional alleles of the MEA gene, termed FER-TILIZATION INDEPENDENT SEED DEVELOPMENT (FIS1), as well as mutations at two other loci, FIS2 and FERTILISATION INDEPENDENT ENDOSPERM (FIE or FIS3), were identified in genetic screens for mutants displaying seed development in the absence of fertilization (Ohad et al. 1996;Chaudhury et al. 1997). The three fisclass mutants show a gametophytic maternal effect: all seeds derived from a mutant female gametophyte (50% in a heterozygote) abort irrespective of the paternal allele. Early development of fis embryos is morphologically indistinguishable from that of wild-type siblings. However, fis embryogenesis is delayed after the globular stage and eventually arrests with oversized heart-shaped embryos surrounded by an abnormally proliferated en-

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Disruption of the plant gene MOM releases transcriptional silencing of methylated genes

Cited by 248 publications

References 30 publications

Functional Redundancy and New Roles for Genes of the Autonomous Floral-Promotion Pathway

Functional Redundancy and New Roles for Genes of the Autonomous Floral-Promotion Pathway

Halogenated Thymidine Analogues Restore the Expression of Silenced Genes without Demethylation

ThePolycomb-group protein MEDEA regulates seed development by controlling expression of the MADS-box genePHERES1

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