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Medea Lars Ita

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The Polycomb-group (PcG) proteins MEDEA, FERTILIZATION INDEPENDENT ENDOSPERM, and FERTILIZATION INDEPENDENT SEED2 regulate seed development in Arabidopsis by controlling embryo and endosperm proliferation. All three of these FIS-class proteins are likely subunits of a multiprotein PcG complex, which epigenetically regulates downstream target genes that were previously unknown. Here we show that the MADS-box gene PHERES1 (PHE1) is commonly deregulated in the fis-class mutants. PHE1 belongs to the evolutionarily ancient type I class of MADS-box proteins that have not yet been assigned any function in plants. Both MEDEA and FIE directly associate with the promoter region of PHE1, suggesting that PHE1 expression is epigenetically regulated by PcG proteins. PHE1 is expressed transiently after fertilization in both the embryo and the endosperm; however, it remains up-regulated in the fis mutants, consistent with the proposed function of the FIS genes as transcriptional repressors. Reduced expression levels of PHE1 in medea mutant seeds can suppress medea seed abortion, indicating a key role of PHE1 repression in seed development. PHE1 expression in a hypomethylated medea mutant background resembles the wild-type expression pattern and is associated with rescue of the medea seed-abortion phenotype. In summary, our results demonstrate that seed abortion in the medea mutant is largely mediated by deregulated expression of the type I MADS-box gene PHE1.


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Medea Lars Ita

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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; Grossniklaus et al. 1998). Additional alleles of the MEA gene, termed FERTILIZATION 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 fis-class 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 endosperm. Furthermore, the central cell of fis mutants undergoes division in the absence of fertilization, suggesting that the primary function of the FIS genes is to control cell proliferation (Grossniklaus et al. 2001).


We are indebted to Valeria Gagliardini and Jaqueline Gheyselinck for excellent technical support. We are grateful to Michael Federer for his help with the histological preparations and Peter Kopf for general lab support. We thank Damian Page for helpful discussions, Célia Baroux for support with microscopical analysis, the Functional Genomics Center Zürich for support of the Affymetrix microarray analysis, Jean-Jacques Pittet for help with the artwork, and Shiv Grewal and Vincent Colot for providing ChIP protocols that served as a basis for our modified procedure. We thank Eric Richards for providing the ddm1 mutant, Jurek Paszkowski for the mom mutant, and Abed Chauhury for the fie mutant. C.K. is supported by Fellowships of EMBO and HFSP and L.H. by the Deutsche Forschungsgemeinschaft. This project was supported by the Kanton of Zürich, grant 31-64061.00 of the Swiss National Science Foundation, and a Searle Scholarship to U.G.


Kibin. (2023). A comparison of the representations of jason and medea in the modern film and in theatre. -examples/a-comparison-of-the-representations-of-jason-and-medea-in-the-modern-film-and-in-theatre-oLADQDlE


"A Comparison of the Representations of Jason and Medea in the Modern Film and in Theatre." Kibin, 2023, www.kibin.com/essay-examples/a-comparison-of-the-representations-of-jason-and-medea-in-the-modern-film-and-in-theatre-oLADQDlE


1. "A Comparison of the Representations of Jason and Medea in the Modern Film and in Theatre." Kibin, 2023. -examples/a-comparison-of-the-representations-of-jason-and-medea-in-the-modern-film-and-in-theatre-oLADQDlE.






"A Comparison of the Representations of Jason and Medea in the Modern Film and in Theatre." Kibin, 2023. -examples/a-comparison-of-the-representations-of-jason-and-medea-in-the-modern-film-and-in-theatre-oLADQDlE.

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