Funkcionalna karakterizacija EML (EMSY-like) proteina kao čitača histonskih modifikacija sa ulogom u regulaciji razvića semena kod Arabidopsis thaliana (L.) Heynh.
Functional characterization of EML (EMSY-like) as histone readers proteins involved in the regulation of Arabidopsis thaliana (L.) Heynh. seed development
Doctoral thesis (Published version)
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In flowering plants, seed development is initiated by double fertilization of the female gametophyte, whereby one sperm cell fuses with the egg cell, while the second fuses with the central cell. The successful and coordinated interaction between the developing seed compartments (seed coat, endosperm and embryo) depends on the balance in parental genome contributions. Any change in the genomic contribution of one parent often leads to severe defects including seed abortion. This represents one of the main obstacles for the engineering of asexual reproduction through seeds (apomixis), and for generating new interspecies hybrids. The repression of auxin synthesis by the Polycomb Repressive Complex 2 (PRC2) is a major mechanism contributing to sensing genome balance. However, current efforts focusing on identification of regulators decreasing PRC2 or elevating auxin levels have not yet resulted in the production of apomictic seed. Evolutionary conserved role of PRC2 during developmental processes in plants is based on the role of this complex to modify histone H3. Furthermore, proteins involved in recognizing histone posttranslational modifications (PTMs) are often included in the regulation of plant development in conjunction with in PRC2. So far a relatively few plant so-called histone readers have been identified to be instrumental for many developmental processes. Results from this study show that EML1 and EML3, proteins that belong to the EMSY-Like Tudor/Agenet protein family, are H3K36me3 histone readers necessary to maintain parental genome balance in Arabidopsis. By analyzing the mutant phenotypes, our results demonstrate that both EML1 and EML3 are required to prevent seed development before fertilization, and to regulate the balance of parental contributions after fertilization. We hypothesize that EML1 and EML3 function to repress paternal gene expression by regulating auxin transport and signaling. Finally, we propose a mechanism of apomictic seed production in Arabidopsis, based on the fine-tuning of auxin flow during seed development, by the histone readers EML1 and EML3, which could be exploited to propagate hybrid seeds, significantly decreasing breeding time and cost.
Keywords:Arabidopsis thaliana; EML; PTMs; Agenet; Tudor; H3K36me3; Histone readers; Apomixis; Seed development; Auxin
Source:Faculty of Biology, University of Belgrade, 2019, 1-135
- Physiological, chemical and molecular analysis of the diversity of selected rare and endangered plant species and application of biotechnology for ex situ conservation and production of biologically active compounds (RS-173024)
- Ohio State University, Ohajo, SAD (NSF MCB-1513807; OPBC2011-003)