Maintenance of spatial gene expression by Polycomb-mediated repression after formation of a vertebrate body plan
Rougeot, Julien ; Chrispijn, Naomi D. ; Aben, Marco ; Elurbe, Dei M. ; Andralojc, Karolina M. ; Murphy, Patrick J. ; Jansen, Pascal W.T.C. ; Vermeulen, Michiel ; Cairns, Bradley R. ; Kamminga, Leonie M. - \ 2019
Development 146 (2019)19. - ISSN 0950-1991
ChIP-seq - Ezh2 - Polycomb - Proteomics - Transcriptomics - Zebrafish
Polycomb group (PcG) proteins are transcriptional repressors that are important regulators of cell fate during embryonic development. Among them, Ezh2 is responsible for catalyzing the epigenetic repressive mark H3K27me3 and is essential for animal development. The ability of zebrafish embryos lacking both maternal and zygotic ezh2 to form a normal body plan provides a unique model for comprehensively studying Ezh2 function during early development in vertebrates. By using a multi-omics approach, we found that Ezh2 is required for the deposition of H3K27me3 and is essential for proper recruitment of Polycomb group protein Rnf2. However, despite the complete absence of PcG-associated epigenetic mark and proteins, only minor changes in H3K4me3 deposition and gene and protein expression occur. These changes were mainly due to local dysregulation of transcription factors outside their normal expression boundaries. Altogether, our results in zebrafish show that Polycomb-mediated gene repression is important immediately after the body plan is formed to maintain spatially restricted expression profiles of transcription factors, and we highlight the differences that exist in the timing of PcG protein action between vertebrate species.
Contribution of methylation regulation of MpDREB2A promoter to drought resistance of Mauls prunifolia
Li, Xuewei ; Xie, Yinpeng ; Lu, Liyuan ; Yan, Mingjia ; Fang, Nan ; Xu, Jidi ; Wang, Liping ; Yan, Yan ; Zhao, Tao ; Nocker, Steve van; Ma, Fengwang ; Liang, Dong ; Guan, Qingmei - \ 2019
Plant and Soil 441 (2019)1-2. - ISSN 0032-079X - p. 15 - 32.
ChIP-seq - DNA methylation - DREB2A - Drought resistance - Gene expression - Malus
Background and aims: Malus prunifolia (Chinese name: Fu Ping Qiu Zi), a wild relative of cultivated apple (Malus x domestica Borkh), is extremely resistant to drought compared with domesticated cultivars, such as ‘Golden Delicious’. However, the molecular mechanisms underlying drought resistance of M. prunifolia have not been characterized. This study investigates a new regulatory mechanism to improve apple drought resistance. Methods: M. prunifolia and ‘Golden Delicious’ were each grafted on M. hupehensis for gene expression analysis. The methylation level of the DREB2A promoter was determined by bisulfite sequencing and ChIP-qPCR. Chromatin immunoprecipitation sequencing (ChIP-seq) was used to identify target genes of MpDREB2A in apple. Results: The exposure to drought stress stimulated the expression level of DREB2A gene more than 100-fold in M. prunifolia, but only 16-fold in ‘Golden Delicious’. This difference in gene expression could not be explained in terms of difference in leaf relative water content. Correspondingly, the methylation level of M. prunifolia DREB2A (MpDREB2A) promoter region was significantly reduced. Additionally, MpDREB2A conferred enhanced drought resistance when ectopically expressed in Arabidopsis. Over 2800 potential downstream target genes of MpDREB2A were identified by ChIP-seq and these downstream genes have diverse potential functions related to stress resistance. Conclusions: Methylation regulation in promoter of MpDREB2A may contribute to the drought resistance of M. prunifolia.
Comparative analysis of binding patterns of MADS-domain proteins in Arabidopsis thaliana
Aerts, Niels ; Bruijn, Suzanne de; Mourik, Hilda van; Angenent, Gerco C. ; Dijk, Aalt D.J. van - \ 2018
BMC Plant Biology 18 (2018)1. - ISSN 1471-2229
CArG-box - ChIP-seq - MADS-domain proteins - Sequence conservation - Transcription factor binding specificity
Background: Correct flower formation requires highly specific temporal and spatial regulation of gene expression. In Arabidopsis thaliana the majority of the master regulators that determine flower organ identity belong to the MADS-domain transcription factor family. The canonical DNA binding motif for this transcription factor family is the CArG-box, which has the consensus CC(A/T)6GG. However, so far, a comprehensive analysis of MADS-domain binding patterns has not yet been performed. Results: Eight publicly available ChIP-seq datasets of MADS-domain proteins that regulate the floral transition and flower formation were analyzed. Surprisingly, the preferred DNA binding motif of each protein was a CArG-box with an NAA extension. Furthermore, motifs of other transcription factors were found in the vicinity of binding sites of MADS-domain transcription factors, suggesting that interaction of MADS-domain proteins with other transcription factors is important for target gene regulation. Finally, conservation of CArG-boxes between Arabidopsis ecotypes was assessed to obtain information about their evolutionary importance. CArG-boxes that fully matched the consensus were more conserved than other CArG-boxes, suggesting that the perfect CArG-box is evolutionary more important than other CArG-box variants. Conclusion: Our analysis provides detailed insight into MADS-domain protein binding patterns. The results underline the importance of an extended version of the CArG-box and provide a first view on evolutionary conservation of MADS-domain protein binding sites in Arabidopsis ecotypes.