Project description:The ability of cells to perceive and translate versatile cues into differential chromatin and transcriptional states is critical for many biological processes1-4. In plants, timely transition to a flowering state is crucial for successful reproduction5-7. EARLY BOLTING IN SHORT DAY (EBS) is a negative transcriptional regulator that prevents premature flowering in Arabidopsis8,9. Here, we revealed that bivalent bromo-adjacent homology (BAH)-plant homeodomain (PHD) reader modules of EBS bind H3K27me3 and H3K4me3, respectively. A subset of EBS-associated genes was co-enriched with H3K4me3, H3K27me3, and the Polycomb repressor complex 2 (PRC2). Interestingly, EBS adopts an auto-inhibition mode to mediate its binding preference switch between H3K27me3 and H3K4me3. This binding balance is critical because disruption of either EBS-H3K27me3 or EBS-H3K4me3 interaction induces EBS-mediated early floral transition. This study identifies a single bivalent chromatin reader capable of recognizing two antagonistic histone marks and reveals a distinct mechanism of interplay between active and repressive chromatin states.The ability of cells to perceive and translate versatile cues into differential chromatin and transcriptional states is critical for many biological processes1-4. In plants, timely transition to a flowering state is crucial for successful reproduction5-7. EARLY BOLTING IN SHORT DAY (EBS) is a negative transcriptional regulator that prevents premature flowering in Arabidopsis8,9. Here, we revealed that bivalent bromo-adjacent homology (BAH)-plant homeodomain (PHD) reader modules of EBS bind H3K27me3 and H3K4me3, respectively. A subset of EBS-associated genes was co-enriched with H3K4me3, H3K27me3, and the Polycomb repressor complex 2 (PRC2). Interestingly, EBS adopts an auto-inhibition mode to mediate its binding preference switch between H3K27me3 and H3K4me3. This binding balance is critical because disruption of either EBS-H3K27me3 or EBS-H3K4me3 interaction induces EBS-mediated early floral transition. This study identifies a single bivalent chromatin reader capable of recognizing two antagonistic histone marks and reveals a distinct mechanism of interplay between active and repressive chromatin states.v
Project description:We conduct herein a systematic study of mRNA recognition and consequent polyadenylation processing of the Arabidopsis mRNA by m6A reader protein CPSF70. Transcriptome-wide characterization of CPSF70-binding sites supporting the recognition m6A-methylated mRNA with CPSF70, and the results of which linked polyadenylation signals recognition. We then perform 3’end sequencing with A-seq2 to identify CPSF70-dependent APA process, showing that CPSF70 modulate m6A–dependent polyadenylation with FUE recognition.
Project description:The ability of a cell to dynamically switch its chromatin between different functional states constitutes a key mechanism regulating gene expression. Histone mark "readers" display distinct binding specificity to different histone modifications and play critical roles in regulating chromatin states. Here, we show a plant-specific histone reader SHORT LIFE (SHL) capable of recognizing both H3K27me3 and H3K4me3 via its bromo-adjacent homology (BAH) and plant homeodomain (PHD) domains, respectively. Detailed biochemical and structural studies suggest a binding mechanism that is mutually exclusive for either H3K4me3 or H3K27me3. Furthermore, we show a genome-wide co-localization of SHL with H3K27me3 and H3K4me3, and that BAH-H3K27me3 and PHD-H3K4me3 interactions are important for SHL-mediated floral repression. Together, our study establishes BAH-PHD cassette as a dual histone methyl-lysine binding module that is distinct from others in recognizing both active and repressive histone marks.
Project description:m6A methylation is the prevalent post-transcriptional modification in eukaryotic mRNAs and provides an essential layer of regulation in organismal development and in disease. The information encoded by m6A methylation is integrated into existing RNA regulatory networks by the binding of an expanding list of m6A readers. An important question is how protein readers that do not contain a canonical m6A-specific YTH domain recognize methylated RNA. Here, we show that the non-canonical reader IMP1 directly recognises the m6A group using a dedicated hydrophobic platform in the KH4 domain, creating a stable and high affinity interaction with the methylated RNA targets. Notably, the recognition of the m6A group is independent from the underlying sequence context, but is layered upon IMP1 strong sequence specificity for GGAC RNA. Together, our data indicate that, contrarily to the well-characterised YTH readers, IMP1 recognises and binds both m6A-methylated and non-methylated RNA targets with high affinity. This suggests that m6A methylation does not provide a general layer of control of IMP1 function, but rather plays a directed role in specific regulatory pathways.
Project description:Arginine methylation is a ubiquitous post-translational modification involved in many biological processes such as transcription, cell signaling and RNA splicing. Tudor domains by far are the major effector domain family for arginine methylation mark recognition. Here we characterize SART3 as a novel selective reader for symmetric dimethylarginine (Rme2s) marks. SART3 harbors a series of HAT (Half-a-TPR) repeats that are aromatic-rich, and it is this region that binds Rme2s motifs. An analysis of the reported structure of the HAT repeats of SART3 identified a putative aromatic cage that potentially “read” the Rme2s-modified motifs, and the key aromatic residues required for Rme2s recognition were identified. We further confirm that this Rme2s reader ability is important for SART3-mediated RNA splicing. Together, our studies revealed that the evolutionarily conserved SART3 HAT domain was a novel reader of Rme2s mark involved in RNA splicing.
Project description:Arginine methylation is a ubiquitous post-translational modification involved in many biological processes such as transcription, cell signaling and RNA splicing. Tudor domains by far are the major effector domain family for arginine methylation mark recognition. Here we characterize SART3 as a novel selective reader for symmetric dimethylarginine (Rme2s) marks. SART3 harbors a series of HAT (Half-a-TPR) repeats that are aromatic-rich, and it is this region that binds Rme2s motifs. An analysis of the reported structure of the HAT repeats of SART3 identified a putative aromatic cage that potentially “read” the Rme2s-modified motifs, and the key aromatic residues required for Rme2s recognition were identified. We further confirm that this Rme2s reader ability is important for SART3-mediated RNA splicing. Together, our studies revealed that the evolutionarily conserved SART3 HAT domain was a novel reader of Rme2s mark involved in RNA splicing.
Project description:Arginine methylation is a ubiquitous post-translational modification involved in many biological processes such as transcription, cell signaling and RNA splicing. Tudor domains by far are the major effector domain family for arginine methylation mark recognition. Here we characterize SART3 as a novel selective reader for symmetric dimethylarginine (Rme2s) marks. SART3 harbors a series of HAT (Half-a-TPR) repeats that are aromatic-rich, and it is this region that binds Rme2s motifs. An analysis of the reported structure of the HAT repeats of SART3 identified a putative aromatic cage that potentially “read” the Rme2s-modified motifs, and the key aromatic residues required for Rme2s recognition were identified. We further confirm that this Rme2s reader ability is important for SART3-mediated RNA splicing. Together, our studies revealed that the evolutionarily conserved SART3 HAT domain was a novel reader of Rme2s mark involved in RNA splicing.