Loss of CG methylation in Marchantia polymorpha causes disorganization of cell division and reveals unique DNA methylation regulatory mechanisms of non-CG methylation

Ikeda, Y., Nishihama, R., Yamaoka, S., Arteaga-Vazquez, M. A., Aguilar-Cruz, A., Grimanelli, D., Pogorelcnik, R., Martienssen, R. A., Yamato, K. T., Kohchi, T., Hirayama, T., Mathieu, O. (August 2018) Loss of CG methylation in Marchantia polymorpha causes disorganization of cell division and reveals unique DNA methylation regulatory mechanisms of non-CG methylation. Plant Cell Physiol, 59 (12). pp. 2421-2431. ISSN 0032-0781

Abstract

DNA methylation is an epigenetic mark that ensures silencing of transposable elements (TEs) and affects gene expression in many organisms. The function of different DNA methylation regulatory pathways has been largely characterized in the model plant Arabidopsis thaliana. However, far less is known about DNA methylation regulation and functions in basal land plants. Here we focus on the liverwort Marchantia polymorpha, an emerging model species that represents a basal lineage of land plants. We identified MpMET, the M. polymorpha orthologue of the METHYLTRANSFERASE 1 (MET1) gene required for maintenance of methylation at CG sites in angiosperms. We generated Mpmet mutants using the CRISPR/Cas9 system, which showed a significant loss of CG methylation and severe morphological changes and developmental defects. The mutants developed many adventitious shoot-like structures, suggesting that MpMET is required for maintaining differentiated cellular identities in the gametophyte. Even though numerous TEs were up-regulated, non-CG methylation was generally highly increased at TEs in the Mpmet mutants. Closer inspection of CHG methylation revealed features unique to M. polymorpha. Methylation of CCG sites in M. polymorpha does not depend on MET1, unlike in A. thaliana and Physcomitrella patens. Furthermore, unlike A. thaliana, M. polymorpha shows higher methylation level at CAG sites than at other CHG contexts and CAG/CTG sites are mostly methylated asymmetrically. Interestingly, CAG and CTG methylation reached comparable levels and symmetry upon loss of CG methylation. Our results highlight the diversity of non-CG methylation regulatory mechanisms in plants.

Item Type:	Paper
Subjects:	bioinformatics bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > DNA methylation bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification bioinformatics > genomics and proteomics > genetics & nucleic acid processing bioinformatics > genomics and proteomics bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > methyltransferase bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > mutations bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > plant proteins bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types
CSHL Authors:	Martienssen, Robert A.
Communities:	CSHL labs > Martienssen lab
Depositing User:	Matthew Dunn
Date:	9 August 2018
Date Deposited:	15 Aug 2018 15:56
Last Modified:	20 Feb 2024 20:52
Related URLs:	Publisher
URI:	https://repository.cshl.edu/id/eprint/37106

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