Language：English  

Polycomb-group (PcG) proteins are major chromatin complexes that regulate gene expression, mainly described as repressors keeping genes in a transcriptional silent state during development. Recent studies have nonetheless suggested that PcG proteins might have additional functions, including on targeting active genes or independently of gene expression regulation. However, the reasons for the implication of PcG and their associated chromatin marks on active genes are still largely unknown. Here, we report that combining mutations for CURLY LEAF (CLF) and LIKE HETEROCHROMATIN PROTEIN1 (LHP1), two Arabidopsis PcG proteins, results in the deregulation of the expression of active genes that are targeted by PcG proteins or enriched in associated chromatin marks. We show that this deregulation is associated with accumulation of small RNAs corresponding to massive degradation of active gene transcripts. We demonstrate that transcriptionally active genes and especially those targeted by PcG are prone to RNA degradation, even though deregulation of RNA degradation following the loss of function of PcG proteins is likely not mediated by a PcG-mediated chromatin environment. Therefore, we highlight that PcG function is essential to maintain an accurate level of RNA degradation to ensure a correct expression level of genes.

DOI： 10.1093/jxb/erac216

Web of Science

PubMed

Publisher：Public Library of Science (PLoS)  

Although paramutation has been well-studied at a few hallmark loci involved in anthocyanin biosynthesis in maize, the cellular and molecular mechanisms underlying the phenomenon remain largely unknown. Previously described actors of paramutation encode components of the RNA-directed DNA-methylation (RdDM) pathway that participate in the biogenesis of 24-nucleotide small interfering RNAs (24-nt siRNAs) and long non-coding RNAs. In this study, we uncover an ARGONAUTE (AGO) protein as an effector of the RdDM pathway that is in charge of guiding 24-nt siRNAs to their DNA target to create de novo DNA methylation. We combined immunoprecipitation, small RNA sequencing and reverse genetics to, first, validate AGO104 as a member of the RdDM effector complex and, then, investigate its role in paramutation. We found that AGO104 binds 24-nt siRNAs involved in RdDM, including those required for paramutation at the b1 locus. We also show that the ago104-5 mutation causes a partial reversion of the paramutation phenotype at the b1 locus, revealed by intermediate pigmentation levels in stem tissues. Therefore, our results place AGO104 as a new member of the RdDM effector complex that plays a role in paramutation at the b1 locus in maize.

DOI： 10.1371/journal.pone.0273695

Web of Science

PubMed

DOI： https://doi.org/10.3390/cells10123534

Language：English   Publisher：Oxford University Press (OUP)  

DOI： 10.1093/pcp/pcab032

Web of Science

Scopus

PubMed

DOI： 10.1111/nph.16710

PubMed

Event date： 2024.2

Language：English   Presentation type：Oral presentation (keynote)  

Venue：Nagoya University   Country：Japan  

Event date： 2024.2

Language：English   Presentation type：Poster presentation  

Venue：Nagoya University   Country：Japan  

Event date： 2024.2

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Nagoya University   Country：Japan  

Event date： 2023.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Sydney   Country：Australia  

Event date： 2023.6

Language：English   Presentation type：Poster presentation  

Venue：Chiba   Country：Japan  

This lecture was part of the plant physiology class for G30 students. It consisted to introduce the plant mineral nutrition and solute transport, as well as the techniques employed to study it, through (i) the presentation of essential nutrients, their availability in soil and how plants can access, and (ii) provide knowledge about the biologically regulated movement of ions through the membrane and then through the plant.
In order to deepen students understanding, we asked them to read academic papers and explain the essence of the study in an oral presentation.