scholarly journals Telomere repeats induce domains of H3K27 methylation in Neurospora

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Kirsty Jamieson ◽  
Kevin J McNaught ◽  
Tereza Ormsby ◽  
Neena A Leggett ◽  
Shinji Honda ◽  
...  
Keyword(s):  
Genome Organization ◽  
Chromosomal Rearrangements ◽  
Histone H3 ◽  
Facultative Heterochromatin ◽  
Heterochromatin Formation ◽  
Cis Acting ◽  
H3k27 Methylation ◽  
And Control ◽  
The Relationship ◽  
Insight Into

Development in higher organisms requires selective gene silencing, directed in part by di-/trimethylation of lysine 27 on histone H3 (H3K27me2/3). Knowledge of the cues that control formation of such repressive Polycomb domains is extremely limited. We exploited natural and engineered chromosomal rearrangements in the fungus Neurospora crassa to elucidate the control of H3K27me2/3. Analyses of H3K27me2/3 in strains bearing chromosomal rearrangements revealed both position-dependent and position-independent facultative heterochromatin. We found that proximity to chromosome ends is necessary to maintain, and sufficient to induce, transcriptionally repressive, subtelomeric H3K27me2/3. We ascertained that such telomere-proximal facultative heterochromatin requires native telomere repeats and found that a short array of ectopic telomere repeats, (TTAGGG)17, can induce a large domain (~225 kb) of H3K27me2/3. This provides an example of a cis-acting sequence that directs H3K27 methylation. Our findings provide new insight into the relationship between genome organization and control of heterochromatin formation.

scholarly journals Telomere repeats induce domains of H3K27 methylation in Neurospora

2017 ◽  
Author(s):  
Kirsty Jamieson ◽  
Kevin J. McNaught ◽  
Tereza Ormsby ◽  
Neena A. Leggett ◽  
Shinji Honda ◽  
...  
Keyword(s):  
Genome Organization ◽  
Chromosomal Rearrangements ◽  
Histone H3 ◽  
Facultative Heterochromatin ◽  
Large Domain ◽  
Heterochromatin Formation ◽  
H3k27 Methylation ◽  
And Control ◽  
The Relationship ◽  
Insight Into

ABSTRACTDevelopment in higher organisms requires selective gene silencing, directed in part by di-/tri-methylation of lysine 27 on histone H3 (H3K27me2/3). Knowledge of the cues that control formation of such repressive Polycomb domains is extremely limited. We exploited natural and engineered chromosomal rearrangements in the fungus Neurospora crassa to elucidate the control of H3K27me2/3. Analyses of H3K27me2/3 in strains bearing chromosomal rearrangements revealed both position-dependent and position-independent facultative heterochromatin. We found that proximity to chromosome ends is necessary to maintain, and sufficient to induce, transcriptionally repressive, subtelomeric H3K27me2/3. We ascertained that such telomere-proximal facultative heterochromatin requires native telomere repeats and found that a short array of ectopic telomere repeats, (TTAGGG)17, can induce a large domain (∼225 kb) of H3K27me2/3. This provides an example of a cis-acting sequence that directs H3K27 methylation. Our findings provide new insight into the relationship between genome organization and control of heterochromatin formation.

scholarly journals ASH1-catalyzed H3K36 methylation drives gene repression and marks H3K27me2/3-competent chromatin

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Vincent T Bicocca ◽  
Tereza Ormsby ◽  
Keyur K Adhvaryu ◽  
Shinji Honda ◽  
Eric U Selker
Keyword(s):  
Rna Polymerase Ii ◽  
Histone H3 ◽  
Gene Repression ◽  
Facultative Heterochromatin ◽  
H3k36 Methylation ◽  
Lysine Methyltransferase ◽  
Inactive Genes ◽  
And Control ◽  
Insight Into ◽  
Active Genes

Methylation of histone H3 at lysine 36 (H3K36me), a widely-distributed chromatin mark, largely results from association of the lysine methyltransferase (KMT) SET-2 with RNA polymerase II (RNAPII), but most eukaryotes also have additional H3K36me KMTs that act independently of RNAPII. These include the orthologs of ASH1, which are conserved in animals, plants, and fungi but whose function and control are poorly understood. We found that Neurospora crassa has just two H3K36 KMTs, ASH1 and SET-2, and were able to explore the function and distribution of each enzyme independently. While H3K36me deposited by SET-2 marks active genes, inactive genes are modified by ASH1 and its activity is critical for their repression. ASH1-marked chromatin can be further modified by methylation of H3K27, and ASH1 catalytic activity modulates the accumulation of H3K27me2/3 both positively and negatively. These findings provide new insight into ASH1 function, H3K27me2/3 establishment, and repression in facultative heterochromatin.

Abstract 15951: Palmitate, Not Oleate, is the Preferred Fatty Acid for Cardiac Triacylglycerol Synthesis

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Stephen C Kolwicz ◽  
Rong Tian
Keyword(s):  
Cell Culture ◽  
13C Nmr Spectroscopy ◽  
Culture Studies ◽  
Triacylglycerol Synthesis ◽  
Culture Models ◽  
Contracting Heart ◽  
And Control ◽  
The Relationship ◽  
Cell Culture Models ◽  
Insight Into

Introduction: Previous studies using cell culture models identified cyto-toxic effects of palmitate and that supplementation with oleate was protective by redirecting palmitate into triacylglycerol (TAG) stores. However, other cull culture studies reported that diacylglycerol transferase 1 (DGAT1), the last enzyme in TAG synthesis, demonstrated a preference for oleate. At present, it is not clear whether the supply of exogenous fatty acids (FA) to the heart is differentially allocated into the endogenous TAG pool. Therefore, the purpose of the present study is to examine the influence of palmitate and/or oleate on cardiac TAG incorporation. METHODS/RESULTS: Hearts were isolated from DGAT1-transgenic (DGAT) and control littermates (CON) and perfused in Langendorff mode with a mixed substrate buffer consisting of glucose, lactate, insulin, and FAs. The FA supply was varied with 0.2mM of both labeled (13C) and unlabeled (12C) FAs in 4 different experiments: 1) 13C/12C palmitate; 2) 13C/12C oleate; 3) 13C palmitate/12C oleate; 4) 13C oleate/12C palmitate. The incorporation of 13C palmitate or 13C oleate into the TAG pool was monitored by 13C NMR spectroscopy. In CON hearts (n=3), the incorporation of palmitate was ~65% higher than oleate when the perfusate contained a homogenous supply of FA. This was also observed in DGAT hearts (n=4) although the incorporation of both palmitate and oleate was ~75% higher compared to CON (P <0.05). In the presence of oleate, palmitate incorporation decreased 25-30% in both CON and DGAT hearts. In contrast, oleate incorporation was diminished by ~50% and ~100% in CON and DGAT hearts, respectively, in the presence of palmitate. CONCLUSIONS: These data suggest that when palmitate and oleate are provided in equal concentrations, palmitate is more readily utilized in the synthesis of endogenous TAG stores in the heart. Furthermore, although overexpression of DGAT increases both oleate and palmitate incorporation, the DGAT1 enzyme demonstrates a preference for palmitate. These findings provide insight into the relationship between exogenous FA supply and endogenous TAG dynamics in the contracting heart.

scholarly journals A conserved RNA degradation complex required for spreading and epigenetic inheritance of heterochromatin

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Gergana Shipkovenska ◽  
Alexander Durango ◽  
Marian Kalocsay ◽  
Steven P Gygi ◽  
Danesh Moazed
Keyword(s):  
Ribosomal Rna ◽  
Rna Processing ◽  
Histone H3 ◽  
Epigenetic Inheritance ◽  
Rna Degradation ◽  
Heterochromatin Formation ◽  
Polynucleotide Kinase ◽  
Ribosomal Rna Processing ◽  
Formation System ◽  
Insight Into

Heterochromatic domains containing histone H3 lysine 9 methylation (H3K9me) can be epigenetically inherited independently of underlying DNA sequence. To gain insight into the mechanisms that mediate epigenetic inheritance, we used a Schizosaccharomyces pombe inducible heterochromatin formation system to perform a genetic screen for mutations that abolish heterochromatin inheritance without affecting its establishment. We identified mutations in several pathways, including the conserved and essential Rix1-associated complex (henceforth the rixosome), which contains RNA endonuclease and polynucleotide kinase activities with known roles in ribosomal RNA processing. We show that the rixosome is required for spreading and epigenetic inheritance of heterochromatin in fission yeast. Viable rixosome mutations that disrupt its association with Swi6/HP1 fail to localize to heterochromatin, lead to accumulation of heterochromatic RNAs, and block spreading of H3K9me and silencing into actively transcribed regions. These findings reveal a new pathway for degradation of heterochromatic RNAs with essential roles in heterochromatin spreading and inheritance.

scholarly journals MET-2, a SETDB1 family methyltransferase, coordinates embryo events through distinct histone H3 methylation states

2018 ◽  
Author(s):  
Beste Mutlu ◽  
Huei-Mei Chen ◽  
David H. Hall ◽  
Susan E. Mango
Keyword(s):  
Developmental Plasticity ◽  
Histone H3 ◽  
Cell Counting ◽  
H3k9 Methylation ◽  
Developmental Potential ◽  
Heterochromatin Formation ◽  
Histone H3 Methylation ◽  
Summary Statement ◽  
Genome Activation ◽  
The Relationship

AbstractDuring the first hours of embryogenesis, formation of higher-order heterochromatin coincides with the loss of developmental potential. Here we examine the relationship between these two processes, and we probe the determinants that contribute to their onset. Mutations that disrupt histone H3 lysine 9 (H3K9) methyltransferases reveal that the methyltransferase MET-2 helps terminate developmental plasticity, likely through mono- and di- methylation of H3K9 (me1/me2), and promotes heterochromatin formation, likely through H3K9me3. We examine how MET-2 is regulated and find that methylated H3K9 appears gradually and depends on the accumulated time of embryogenesis. H3K9me is independent of zygotic genome activation or cell counting. These data reveal how central events are synchronized during embryogenesis and distinguish distinct roles for different H3K9 methylation states.Summary StatementDuring early embryogenesis, heterochromatin formation and loss of developmental plasticity are coordinately regulated by distinct Histone H3 Lysine 9 (H3K9) methylation states, by the methyltransferase MET-2.

scholarly journals Professionalizing and Profiting: The Rise of Intermediaries in the Social Media Influencer Industry

2019 ◽  
Vol 5 (1) ◽  
pp. 205630511983258 ◽  
Author(s):  
Ryan Stoldt ◽  
Mariah Wellman ◽  
Brian Ekdale ◽  
Melissa Tully
Keyword(s):  
Social Media ◽  
Digital Media ◽  
Tourism Industry ◽  
Third Party ◽  
Travel And Tourism ◽  
The Social ◽  
And Control ◽  
The Relationship ◽  
Depth Interviews ◽  
Insight Into

This study examines the relationship between travel influencers (e.g., bloggers and social media personalities) and destination marketers within the changing travel and tourism industry. Through in-depth interviews, observations, and document analysis, we explore the tensions between travel influencers and destination marketers that shape the way travel is promoted, labor is compensated, and professional structures are negotiated. We examine a new breed of travel and tourism worker—intermediaries who seek to professionalize and formalize the relationship between influencers and destination marketers while simultaneously solidifying their own role within the industry. Intermediaries promote and facilitate relationships based on structured flexibility—formalized agreements designed to satisfy a brand’s campaign goals yet open enough for influencers to pursue their unique needs. By examining the relationships between digital content creators, destination marketers, and third-party intermediaries, this article provides insight into how digital media industries negotiate the tension between participation and control.

Spontaneous Thought, Insight, and Control in Lucid Dreams

2018 ◽  
Author(s):  
Jennifer M. Windt ◽  
Ursula Voss
Keyword(s):  
Cognitive Processes ◽  
Lucid Dreaming ◽  
Research Findings ◽  
Dream Imagery ◽  
Spontaneous Thought ◽  
The One ◽  
And Control ◽  
The Relationship ◽  
Insight Into ◽  
Shed Light

Dreams are sometimes described as an intensified form of spontaneous waking thought. Lucid dreams may seem to be a counterexample, because metacognitive insight into the fact that one is now dreaming is often associated with the ability to deliberately control the ongoing dream. This chapter uses conceptual considerations and empirical research findings to argue that lucid dreaming is in fact a promising and rich target for the future investigation of spontaneous thought. In particular, the investigation of dream lucidity can shed light on the relationship between metacognitive insight and control, on the one hand, and the spontaneous, largely imagistic cognitive processes that underlie the formation of dream imagery, on the other hand. In some cases, even lucid insight itself can be described as the outcome of spontaneous processes, rather than as resulting from conscious and deliberate reasoning. This raises new questions about the relationship between metacognitive awareness and spontaneous thought.

X chromosome inactivation: heterogeneity of heterochromatin

2008 ◽  
Vol 86 (5) ◽  
pp. 370-379 ◽  
Author(s):  
Sharan K. Sidhu ◽  
Jakub Minks ◽  
Samuel C. Chang ◽  
Allison M. Cotton ◽  
Carolyn J. Brown
Keyword(s):  
X Chromosome ◽  
X Chromosome Inactivation ◽  
X Inactivation ◽  
Model Systems ◽  
Chromosome Inactivation ◽  
Human Model ◽  
Facultative Heterochromatin ◽  
Cis Acting ◽  
Insight Into

The silent X chromosome in mammalian females is a classic example of facultative heterochromatin, the term highlighting the compacted and inactive nature of the chromosome. However, it is now clear that the heterochromatin of the inactive X is not homogeneous — as indeed, not all genes on the inactive X are silenced. We summarize known features and events of X inactivation in different mouse and human model systems, and highlight the heterogeneity of chromatin along the inactive X. Characterizing this heterogeneity is likely to provide insight into the cis-acting sequences involved in X chromosome inactivation.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

From Container to Claustrum: Projective Identification in Couples

2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Tamara Feldman
Keyword(s):  
Psychological Health ◽  
Projective Identification ◽  
The Self ◽  
The Other ◽  
Intimate Partners ◽  
And Control ◽  
The Relationship ◽  
As If

This paper is a contribution to the growing literature on the role of projective identification in understanding couples' dynamics. Projective identification as a defence is well suited to couples, as intimate partners provide an ideal location to deposit unwanted parts of the self. This paper illustrates how projective identification functions differently depending on the psychological health of the couple. It elucidates how healthier couples use projective identification more as a form of communication, whereas disturbed couples are inclined to employ it to invade and control the other, as captured by Meltzer's concept of "intrusive identification". These different uses of projective identification affect couples' capacities to provide what Bion called "containment". In disturbed couples, partners serve as what Meltzer termed "claustrums" whereby projections are not contained, but imprisoned or entombed in the other. Applying the concept of claustrum helps illuminate common feelings these couples express, such as feeling suffocated, stifled, trapped, held hostage, or feeling as if the relationship is killing them. Finally, this paper presents treatment challenges in working with more disturbed couples.

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