Project description:This work uncovers a novel and biologically significant mechanism that directly connects nutrient availability to histone modifications and gene transcription. We report that glycolysis promotes histone H3K4 trimethylation (H3K4me3) by activating Tpk2, a catalytic subunit of protein kinase A (PKA) via the Ras-cyclic AMP (cAMP) pathway. Glucose-activated PKA (Tpk2) inhibits Jhd2-catalyzed H3K4 demethylation by phosphorylating Jhd2 at serine 321 and serine 340. In addition, Tpk2- catalyzed Jhd2 phosphorylation promotes H3K14ac by preventing the binding of Rpd3 at chromatin.
Project description:H3K4me3 is catalyzed by the Set1/MLL family of methyltransferases, whose function in catalyzing H3K4me3 is unique. Impaired function of Set1/MLL family members can lead to many abnormalities, such as bone and nerve defects, leukemia, and even death. Although the Set1 family plays an important regulatory role in various biological processes, it is still unclear how the Set1 protein itself is regulated and how protein levels are maintained. Due to the numerous homologues, complex composition, and high molecular weight of Set1 in higher organisms, especially humans, related research is greatly limited. In brewing yeast, Set1 is the only methyltransferase that catalyzes H3K4me3 and is highly conserved between species. Therefore, yeast is an ideal model for studying the functions and mechanisms of the Set1 family. In addition, Set1 protein plays an important role in regulating gene transcription, promoting telomere silencing, and maintaining cell lifespan. The Set1 family also plays an important regulatory role in the occurrence and development of various cancers.
Project description:The glycolytic enzyme, pyruvate kinase Pyk1 maintains telomere heterochromatin by phosphorylating histone H3T11 (H3pT11), which promotes SIR (silent information regulator) complex binding at telomeres and prevents autophagy-mediated Sir2 degradation. However, the exact action mechanism of H3pT11 is poorly understood. Here, we report that H3pT11 directly inhibits Dot1-catalyzed H3K79 tri-methylation (H3K79me3) and uncover how this histone crosstalk regulates autophagy and telomere silencing. Mechanistically, Pyk1-catalyzed H3pT11 directly reduces the binding of Dot1 to chromatin and inhibits Dot1-catalyzed H3K79me3, which leads to transcriptional repression of autophagy genes and reduced autophagy. Despite the antagonism between H3pT11 and H3K79me3, they work together to promote the binding of SIR complex at telomeres to maintain telomere silencing. Furthermore, we identify Reb1 as a telomere-associated factor that recruits Pyk1-containing SESAME (Serine-responsive SAM36 taining Metabolic Enzyme) complex to telomere regions to phosphorylate H3T11 and prevent the invasion of H3K79me3 from euchromatin into heterochromatin to maintain telomere silencing. Together, these results uncover a novel histone crosstalk and provide insights into dynamic regulation of silent heterochromatin and autophagy in response to cell metabolism.
Project description:Castanopsis fissa is an evergreen broad-leaved species of the cone genus Castanopsis in the family Fagaceae, which is widely distributed and is an excellent native species in Guangdong Province of China. This species has a well-developed root system, excellent soil-fixing power, and better soil and water conservation ability and has the characteristics of barren tolerance, strong sprouting power, abundant and easily decomposed dead leaves, etc. Therefore, C. fissa is not only a pioneer species for postdestruction sprouting forests but also a highly potential ecological public welfare forest tree species. Moreover, due to its beautiful shape, wide canopy and various colors, it has become an ideal tree for landscaping and ornamental purposes. However, there is a basic gap in knowledge in the reports on the drought resistance or drought tolerance genes of C. fissa. Based on the above details, in this study, 2-year-old C. fissa seedlings were used as the study material to investigate the physiological response under drought stress by a potted drought experiment, and we also compared and analyzed the differentially expressed proteins (DEPs) under different periods of drought stress by TMT quantitative labeling protein to prepare a preliminary study on the physiological response and proteomic mechanism of C. fissa adaptation to drought stress.
Project description:Paired-end sequencing study of nucleosomes and immuno-precipitated Tfc1 and Brf1 complexes from MNase-digested nuclei. Nucleosomal DNA, input DNA and DNA from immunopurified TFIIIB and TFIIIC complexes (IP) were subjected to paired-end sequencing.
Project description:Chd proteins are ATP-dependent chromatin remodeling enzymes implicated in biological functions from transcriptional elongation to control of pluripotency. Here, we examine roles of Chd1 in replication- independent dynamics of histone H3 in yeast. Using genome-wide ChIP on chip analysis, we find that Chd1 influences histone turnover at the 5M-bM-^@M-^Y and 3M-bM-^@M-^Y ends of genes, accelerating H3 replacement at the 5M-bM-^@M-^Y ends of genes while protecting the 3M-bM-^@M-^Y ends of genes from excessive H3 turnover. Although consistent with a direct role for Chd1 in exchange, these results may indicate that Chd1 stabilizes nucleosomes perturbed by transcription. Curiously, we observe a strong effect of gene length on Chd1M-bM-^@M-^Ys effects on H3 turnover. Finally, we show that Chd1 also affects histone H3K4 and H3K36 methylation patterns over genes, likely as a consequence of its effects on histone replacement. In control experiments, we measure effects of deletion of CHD1 on RNA polymerase II distribution across the genome and on gene expression. We also examine the effect of deleting the TOP1 gene, alone and in combination with deletion of CHD1, on histone replacement. Taken together, our results emphasize a role for Chd1 in histone replacement in both budding yeast and Drosophila, and surprisingly show that the major effects of Chd1 on turnover occur at the 3M-bM-^@M-^Y ends of genes. ChIP on chip experiments, compares IP of newly expressed, Flag-tagged histone H3 to total histone H3.