Browsing by Subject "Methyltransferases"

Now showing 1 - 9 of 9
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    Allele-specific control of rodent and human lncRNA KMT2E-AS1 promotes hypoxic endothelial pathology in pulmonary hypertension
    (American Association for the Advancement of Science, 2024) Tai, Yi-Yin; Yu, Qiujun; Tang, Ying; Sun, Wei; Kelly, Neil J.; Okawa, Satoshi; Zhao, Jingsi; Schwantes-An, Tae-Hwi; Lacoux, Caroline; Torrino, Stephanie; Al Aaraj, Yassmin; El Khoury, Wadih; Negi, Vinny; Liu, Mingjun; Corey, Catherine G.; Belmonte, Frances; Vargas, Sara O.; Schwartz, Brian; Bhat, Bal; Chau, B. Nelson; Karnes, Jason H.; Satoh, Taijyu; Barndt, Robert J.; Wu, Haodi; Parikh, Victoria N.; Wang, Jianrong; Zhang, Yingze; McNamara, Dennis; Li, Gang; Speyer, Gil; Wang, Bing; Shiva, Sruti; Kaufman, Brett; Kim, Seungchan; Gomez, Delphine; Mari, Bernard; Cho, Michael H.; Boueiz, Adel; Pauciulo, Michael W.; Southgate, Laura; Trembath, Richard C.; Sitbon, Olivier; Humbert, Marc; Graf, Stefan; Morrell, Nicholas W.; Rhodes, Christopher J.; Wilkins, Martin R.; Nouraie, Mehdi; Nichols, William C.; Desai, Ankit A.; Bertero, Thomas; Chan, Stephen Y.; Medicine, School of Medicine
    Hypoxic reprogramming of vasculature relies on genetic, epigenetic, and metabolic circuitry, but the control points are unknown. In pulmonary arterial hypertension (PAH), a disease driven by hypoxia inducible factor (HIF)-dependent vascular dysfunction, HIF-2α promoted expression of neighboring genes, long noncoding RNA (lncRNA) histone lysine N-methyltransferase 2E-antisense 1 (KMT2E-AS1) and histone lysine N-methyltransferase 2E (KMT2E). KMT2E-AS1 stabilized KMT2E protein to increase epigenetic histone 3 lysine 4 trimethylation (H3K4me3), driving HIF-2α-dependent metabolic and pathogenic endothelial activity. This lncRNA axis also increased HIF-2α expression across epigenetic, transcriptional, and posttranscriptional contexts, thus promoting a positive feedback loop to further augment HIF-2α activity. We identified a genetic association between rs73184087, a single-nucleotide variant (SNV) within a KMT2E intron, and disease risk in PAH discovery and replication patient cohorts and in a global meta-analysis. This SNV displayed allele (G)-specific association with HIF-2α, engaged in long-range chromatin interactions, and induced the lncRNA-KMT2E tandem in hypoxic (G/G) cells. In vivo, KMT2E-AS1 deficiency protected against PAH in mice, as did pharmacologic inhibition of histone methylation in rats. Conversely, forced lncRNA expression promoted more severe PH. Thus, the KMT2E-AS1/KMT2E pair orchestrates across convergent multi-ome landscapes to mediate HIF-2α pathobiology and represents a key clinical target in pulmonary hypertension.
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    Epigenetic Editing of Ascl1 Gene in Neural Stem Cells by Optogenetics
    (SpringerNature, 2017-02-09) Lo, Chiao-Ling; Choudhury, Samrat Roy; Irudayaraj, Joseph; Zhou, Feng C.; Department of Anatomy & Cell Biology, IU School of Medicine
    Enzymes involved in epigenetic processes such as methyltransferases or demethylases are becoming highly utilized for their persistent DNA or histone modifying efficacy. Herein, we have developed an optogenetic toolbox fused to the catalytic domain (CD) of DNA-methyltransferase3A (DNMT3A-CD) or Ten-Eleven Dioxygenase-1 (TET1-CD) for loci-specific alteration of the methylation state at the promoter of Ascl1 (Mash1), a candidate proneuron gene. Optogenetical protein pairs, CRY2 linked to DNMT3A-CD or TET1-CD and CIB1 fused to a Transcription Activator-Like Element (TALE) locating an Ascl1 promoter region, were designed for site specific epigenetic editing. A differentially methylated region at the Ascl1 promoter, isolated from murine dorsal root ganglion (hypermethylated) and striated cells (hypomethylated), was targeted with these optogenetic-epigenetic constructs. Optimized blue-light illumination triggered the co-localization of TALE constructs with DNMT3A-CD or TET1-CD fusion proteins at the targeted site of the Ascl1 promoter. We found that this spatiotemporal association of the fusion proteins selectively alters the methylation state and also regulates gene activity. This proof of concept developed herein holds immense promise for the ability to regulate gene activity via epigenetic modulation with spatiotemporal precision.
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    Identification of nonhistone substrates of the lysine methyltransferase PRDM9
    (Elsevier, 2023) Hanquier, Jocelyne N.; Sanders, Kenidi; Berryhill, Christine A.; Sahoo, Firoj K.; Hudmon, Andy; Vilseck, Jonah Z.; Cornett, Evan M.; Biochemistry and Molecular Biology, School of Medicine
    Lysine methylation is a dynamic, posttranslational mark that regulates the function of histone and nonhistone proteins. Many of the enzymes that mediate lysine methylation, known as lysine methyltransferases (KMTs), were originally identified to modify histone proteins but have also been discovered to methylate nonhistone proteins. In this work, we investigate the substrate selectivity of the KMT PRDM9 to identify both potential histone and nonhistone substrates. Though normally expressed in germ cells, PRDM9 is significantly upregulated across many cancer types. The methyltransferase activity of PRDM9 is essential for double-strand break formation during meiotic recombination. PRDM9 has been reported to methylate histone H3 at lysine residues 4 and 36; however, PRDM9 KMT activity had not previously been evaluated on nonhistone proteins. Using lysine-oriented peptide libraries to screen potential substrates of PRDM9, we determined that PRDM9 preferentially methylates peptide sequences not found in any histone protein. We confirmed PRDM9 selectivity through in vitro KMT reactions using peptides with substitutions at critical positions. A multisite λ-dynamics computational analysis provided a structural rationale for the observed PRDM9 selectivity. The substrate selectivity profile was then used to identify putative nonhistone substrates, which were tested by peptide spot array, and a subset was further validated at the protein level by in vitro KMT assays on recombinant proteins. Finally, one of the nonhistone substrates, CTNNBL1, was found to be methylated by PRDM9 in cells.
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    m6A RNA methylation facilitates pre-mRNA 3’-end formation and is essential for viability of Toxoplasma gondii
    (PLOS, 2021-07-29) Holmes, Michael J.; Padgett, Leah R.; Bastos, Matheus S.; Sullivan, William J., Jr.; Pharmacology and Toxicology, School of Medicine
    Toxoplasma gondii is an obligate intracellular parasite that can cause serious opportunistic disease in the immunocompromised or through congenital infection. To progress through its life cycle, Toxoplasma relies on multiple layers of gene regulation that includes an array of transcription and epigenetic factors. Over the last decade, the modification of mRNA has emerged as another important layer of gene regulation called epitranscriptomics. Here, we report that epitranscriptomics machinery exists in Toxoplasma, namely the methylation of adenosines (m6A) in mRNA transcripts. We identified novel components of the m6A methyltransferase complex and determined the distribution of m6A marks within the parasite transcriptome. m6A mapping revealed the modification to be preferentially located near the 3'-boundary of mRNAs. Knockdown of the m6A writer components METTL3 and WTAP resulted in diminished m6A marks and a complete arrest of parasite replication. Furthermore, we examined the two proteins in Toxoplasma that possess YTH domains, which bind m6A marks, and showed them to be integral members of the cleavage and polyadenylation machinery that catalyzes the 3'-end processing of pre-mRNAs. Loss of METTL3, WTAP, or YTH1 led to a defect in transcript 3'-end formation. Together, these findings establish that the m6A epitranscriptome is essential for parasite viability by contributing to the processing of mRNA 3'-ends.
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    The protective role of DOT1L in UV-induced melanomagenesis
    (Nature Publishing Group, 2018-01-17) Zhu, Bo; Chen, Shuyang; Wang, Hongshen; Yin, Chengqian; Han, Changpeng; Peng, Cong; Liu, Zhaoqian; Wan, Lixin; Zhang, Zhang; Zhang, Jie; Lian, Christine G.; Ma, Peilin; Xu, Zhi-xiang; Prince, Sharon; Wang, Tao; Gao, Xiumei; Shi, Yujiang; Liu, Dali; Liu, Min; Wei, Wenyi; Wei, Zhi; Pan, Jingxuan; Wang, Yongjun; Xuan, Zhenyu; Hess, Jay L.; Hayward, Nicholas K.; Goding, Colin R.; Chen, Xiang; Zhou, Jun; Cui, Rutao; Pathology and Laboratory Medicine, School of Medicine
    The DOT1L histone H3 lysine 79 (H3K79) methyltransferase plays an oncogenic role in MLL-rearranged leukemogenesis. Here, we demonstrate that, in contrast to MLL-rearranged leukemia, DOT1L plays a protective role in ultraviolet radiation (UVR)-induced melanoma development. Specifically, the DOT1L gene is located in a frequently deleted region and undergoes somatic mutation in human melanoma. Specific mutations functionally compromise DOT1L methyltransferase enzyme activity leading to reduced H3K79 methylation. Importantly, in the absence of DOT1L, UVR-induced DNA damage is inefficiently repaired, so that DOT1L loss promotes melanoma development in mice after exposure to UVR. Mechanistically, DOT1L facilitates DNA damage repair, with DOT1L-methylated H3K79 involvement in binding and recruiting XPC to the DNA damage site for nucleotide excision repair (NER). This study indicates that DOT1L plays a protective role in UVR-induced melanomagenesis.
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    RNA alternative splicing impacts the risk for alcohol use disorder
    (Springer Nature, 2023) Li, Rudong; Reiter, Jill L.; Chen, Andy B.; Chen, Steven X.; Foroud, Tatiana; Edenberg, Howard J.; Lai, Dongbing; Liu, Yunlong; Medical and Molecular Genetics, School of Medicine
    Alcohol use disorder (AUD) is a complex genetic disorder characterized by problems arising from excessive alcohol consumption. Identifying functional genetic variations that contribute to risk for AUD is a major goal. Alternative splicing of RNA mediates the flow of genetic information from DNA to gene expression and expands proteome diversity. We asked whether alternative splicing could be a risk factor for AUD. Herein, we used a Mendelian randomization (MR)-based approach to identify skipped exons (the predominant splicing event in brain) that contribute to AUD risk. Genotypes and RNA-seq data from the CommonMind Consortium were used as the training dataset to develop predictive models linking individual genotypes to exon skipping in the prefrontal cortex. We applied these models to data from the Collaborative Studies on Genetics of Alcoholism to examine the association between the imputed cis-regulated splicing outcome and the AUD-related traits. We identified 27 exon skipping events that were predicted to affect AUD risk; six of these were replicated in the Australian Twin-family Study of Alcohol Use Disorder. Their host genes are DRC1, ELOVL7, LINC00665, NSUN4, SRRM2 and TBC1D5. The genes downstream of these splicing events are enriched in neuroimmune pathways. The MR-inferred impacts of the ELOVL7 skipped exon on AUD risk was further supported in four additional large-scale genome-wide association studies. Additionally, this exon contributed to changes of gray matter volumes in multiple brain regions, including the visual cortex known to be involved in AUD. In conclusion, this study provides strong evidence that RNA alternative splicing impacts the susceptibility to AUD and adds new information on AUD-relevant genes and pathways. Our framework is also applicable to other types of splicing events and to other complex genetic disorders.
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    The role of CFP1 in murine embryonic stem cell function and liver regeneration
    (2015-08) Mahadevan, Jyothi; Skalnik, David G.; Goebl, Mark G.; Harrington, Maureen A.; Herring, B. Paul
    CXXC finger protein 1 (Cfp1), a component of the Set1 histone methyltransferase complex, is a critical epigenetic regulator of both histone and cytosine methylation. Murine embryos lacking Cfp1 are unable to gastrulate and Cfp1-null embryonic stem (ES) cells fail to undergo cellular differentiation in vitro. However, expression of wild type Cfp1 in Cfp1-null ES cells rescues differentiation capacity, suggesting that dynamic epigenetic changes occurring during lineage specification require Cfp1. The domain structure of Cfp1 consists of a DNA binding CXXC domain and an N-terminal plant homeodomain (PHD). PHDs are frequently observed in chromatin remodeling proteins, functioning as reader modules for histone marks. However, the histone binding properties and underlying functional significance of Cfp1 PHD are largely unknown. My research revealed that Cfp1 PHD directly and specifically binds to histone H3K4me1/me2/me3 marks. A point mutation that abolishes binding to methylated H3K4 (W49A) does not affect rescue of cellular differentiation, but, point mutations that abolish both methylated H3K4 (W49A) and DNA (C169A) binding result in defective in vitro differentiation, indicating that PHD and CXXC exhibit redundant functions. The mammalian liver has the unique ability to regenerate following injury. Previous studies indicated that Cfp1 is essential for hematopoiesis in zebrafish and mice. I hypothesized that Cfp1 additionally plays a role in liver development and regeneration. To understand the importance of Cfp1 in liver development and regeneration, I generated a mouse line lacking Cfp1 specifically in the liver (Cfp1fl/fl Alb-Cre+). Around 40% of these mice display a wasting phenotype and die within a year. Livers of these mice have altered global H3K4me3 levels and often exhibit regenerative nodules. Most importantly, livers of these mice display an impaired regenerative response following partial hepatectomy. Collectively, these findings establish Cfp1 as an epigenetic regulator essential for ES cell function and liver homeostasis and regeneration.
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    Setd1 Histone 3 Lysine 4 Methyltransferase Complex Components in Epigenetic Regulation
    (2011-03-16) Pick-Franke, Patricia A.; Skalnik, David Gordon; Chun, Kristin; Rhodes, Simon J.
    Setd1 histone 3 lysine 4 methyltransferases are critical for epigenetic regulation and gene expression. Setd1a is multiprotein complex comprised of several critical subunits including wdr82, which is essential for embryonic development, and cfp1, critical for regulation of both activation and repression of transcriptional programs required in basic and developmental cellular processes.