The role of ATXR6 expression in modulating genome stability and transposable element repression in Arabidopsis.

Abstract

ARABIDOPSIS TRITHORAX-RELATED PROTEIN 5 (ATXR5) AND ATXR6 are required for the deposition of H3K27me1 and for maintaining genomic stability in Arabidopsis Reduction of ATXR5/6 activity results in activation of DNA damage response genes, along with tissue-specific derepression of transposable elements (TEs), chromocenter decompaction, and genomic instability characterized by accumulation of excess DNA from heterochromatin. How loss of ATXR5/6 and H3K27me1 leads to these phenotypes remains unclear. Here we provide extensive characterization of the atxr5/6 hypomorphic mutant by comprehensively examining gene expression and epigenetic changes in the mutant. We found that the tissue-specific phenotypes of TE derepression and excessive DNA in this atxr5/6 mutant correlated with residual ATXR6 expression from the hypomorphic ATXR6 allele. However, up-regulation of DNA damage genes occurred regardless of ATXR6 levels and thus appears to be a separable process. We also isolated an atxr6-null allele which showed that ATXR5 and ATXR6 are required for female germline development. Finally, we characterize three previously reported suppressors of the hypomorphic atxr5/6 mutant and show that these rescue atxr5/6 via distinct mechanisms, two of which involve increasing H3K27me1 levels.

• Authors: Magdalena E Potok, Zhenhui Zhong, Colette L Picard, Qikun Liu, Truman Do, Cassidy E Jacobsen, Ocean Sakr, Bilguudei Naranbaatar, Ruwan Thilakaratne, Zhanna Khnkoyan, Megan Purl, Harrison Cheng, Helena Vervaet, Suhua Feng, Shima Rayatpisheh, James A Wohlschlegel, Ronan C O'Malley, Joseph R Ecker, Steven E Jacobsen
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 119 Issue 3 (01 18 2022) ISSN: 1091-6490 [Electronic] United States
• PMID: 35027454 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2022 the Author(s). Published by PNAS.

Chemical References

• Arabidopsis Proteins
• DNA Transposable Elements
• Heterochromatin
• Histones
• ATXR5 protein, Arabidopsis
• ATXR6 protein, Arabidopsis
• Methyltransferases

Topics

• Alleles
• Arabidopsis (genetics, metabolism)
• Arabidopsis Proteins (genetics, metabolism)
• DNA Transposable Elements
• Epigenesis, Genetic
• Gene Expression Regulation, Plant
• Genomic Instability
• Heterochromatin (metabolism)
• Histones (metabolism)
• Methyltransferases (genetics, metabolism)
• Mutation
• Phenotype
• Transcriptome