Restriction of Cellular Plasticity of Differentiated Cells Mediated by Chromatin Modifiers, Transcription Factors and Protein Kinases

Rahe, Dylan P; Hobert, Oliver

doi:10.1534/g3.119.400328

“…In C . elegans , a CRISPR generated OGT-1-GFP allele is functional and is ubiquitously expressed throughout somatic cells in the nucleus, consistent with previous observations ( S4D and S5D Figs) [ 24 ]. Therefore, we used tissue specific promoters to test which tissues require ogt-1 expression for gpdh-1 induction by hypertonic stress.…”

Section: Resultssupporting

confidence: 90%

The O-GlcNAc transferase OGT is a conserved and essential regulator of the cellular and organismal response to hypertonic stress

Urso

¹

,

Comly

²

,

Hanover

³

et al. 2020

View full text Add to dashboard Cite

The conserved O -GlcNAc transferase OGT O -GlcNAcylates serine and threonine residues of intracellular proteins to regulate their function. OGT is required for viability in mammalian cells, but its specific roles in cellular physiology are poorly understood. Here we describe a conserved requirement for OGT in an essential aspect of cell physiology: the hypertonic stress response. Through a forward genetic screen in Caenorhabditis elegans , we discovered OGT is acutely required for osmoprotective protein expression and adaptation to hypertonic stress. Gene expression analysis shows that ogt-1 functions through a post-transcriptional mechanism. Human OGT partially rescues the C . elegans phenotypes, suggesting that the osmoregulatory functions of OGT are ancient. Intriguingly, expression of O-GlcNAcylation-deficient forms of human or worm OGT rescue the hypertonic stress response phenotype. However, expression of an OGT protein lacking the tetracopeptide repeat (TPR) domain does not rescue. Our findings are among the first to demonstrate a specific physiological role for OGT at the organismal level and demonstrate that OGT engages in important molecular functions outside of its well described roles in post-translational O-GlcNAcylation of intracellular proteins.

show abstract

“…In C. elegans, functional endogenously GFP tagged ogt-1 is ubiquitously expressed in the nucleus, consistent with previous observations ( Figure S4C and S5A) (22). Therefore, we used tissue specific promoters to test which tissues require ogt-1 expression for gpdh-1 induction by hypertonic stress.…”

Section: Non-canonical Activity Of Ogt-1 In the Hypodermis Regulates supporting

confidence: 85%

“…C. elegans is the primary genetic model system for studies of ogt-1 because it is the only organism in which loss of ogt-1 is viable (25,26). This has allowed many previous studies to parse the roles of ogt-1 in lifespan, metabolism, innate immunity, behavior, neuron function, stress responses, cell fate, and autophagy (18,22,25,(27)(28)(29)(30)(31)(32)(33)(34)(35)(36). Importantly, most of these studies utilized global ogt-1 knockdown, which eliminates both O-GlcNAcylation-dependent and -independent functions of ogt-1.…”

Section: Discussionmentioning

confidence: 99%

TheO-GlcNAc transferase OGT is a conserved and essential regulator of the cellular and organismal response to hypertonic stress

Urso

¹

,

Comly

²

,

Hanover

³

et al. 2020

Preprint

View full text Add to dashboard Cite

The conserved O-GlcNAc transferase OGT O-GlcNAcylates serine and threonine residues of intracellular proteins to regulate their function. OGT is required for viability in mammalian cells, but its specific roles in cellular physiology are poorly understood. Here we describe a conserved requirement for OGT in an essential aspect of cell physiology: the hypertonic stress response. Through a forward genetic screen in Caenorhabditis elegans, we discovered OGT is acutely required for osmoprotective protein expression and adaptation to hypertonic stress. Gene expression analysis shows that ogt-1 functions through a post-transcriptional mechanism. Human OGT partially rescues the C. elegans phenotypes, suggesting that the osmoregulatory functions of OGT are ancient. Intriguingly, mutations that ablate O-GlcNAcylation activity in either human or C. elegansOGT rescue the hypertonic stress response phenotype. Our findings are among the first to demonstrate a specific physiological role for OGT at the organismal level and demonstrate that OGT engages in important molecular functions outside of its well described roles in post-translational O-GlcNAcylation of intracellular proteins. Author SummaryThe ability to sense and adapt to changes in the environment is an essential feature of cellular life. Changes in environmental salt and water concentrations can rapidly cause cell volume swelling or shrinkage and, if left unchecked, will lead to cell and organismal death. All organisms have developed similar physiological strategies for maintaining cell volume. However, the molecular mechanisms that control these physiological outputs are not well understood in animals. Using unbiased genetic screening in C. elegans, we discovered that a highly conserved enzyme called O-GlcNAc transferase (OGT) is essential for regulating physiological responses to increased environmental solute levels. A human form of OGT can functionally substitute for worm OGT, showing that this role is conserved across evolution. Surprisingly, the only known enzymatic activity of OGT was not required for this role, suggesting this enzyme has important undescribed molecular functions. Our studies reveal a new animal-specific role for OGT in the response to osmotic stress and show that C. elegans is an important model for defining the conserved molecular mechanisms that respond to alterations in cell volume.

show abstract

“…These results are consistent with the role of DOT1 and H3K79me2 in ensuring proper animal development despite changing environmental conditions through the regulation of enhancers. Moreover, the identification of dot-1.1 mutants in screens for inhibitors of cellular plasticity in C. elegans [23] further supports its role in developmental enhancer control.…”

Section: Discussionmentioning

confidence: 74%

“…Therefore, the developmental phenotypes of animals lacking H3K79 methylation are most likely due to a reduced activation of enhancer-controlled lineage-specific genes. Consistent with the role of DOT1 in promoting lineage specification, dot-1.1 reduction-in-function mutations have recently been isolated in a screen for inhibitors of developmental plasticity [ 23 ].…”

Section: Introductionmentioning

confidence: 99%

Caenorhabditis elegans Deficient in DOT-1.1 Exhibit Increases in H3K9me2 at Enhancer and Certain RNAi-Regulated Regions

Esse

¹

,

Grishok

²

2020

Cells

View full text Add to dashboard Cite

The methylation of histone H3 at lysine 79 is a feature of open chromatin. It is deposited by the conserved histone methyltransferase DOT1. Recently, DOT1 localization and H3K79 methylation (H3K79me) have been correlated with enhancers in C. elegans and mammalian cells. Since earlier research implicated H3K79me in preventing heterochromatin formation both in yeast and leukemic cells, we sought to inquire whether a H3K79me deficiency would lead to higher levels of heterochromatic histone modifications, specifically H3K9me2, at developmental enhancers in C. elegans. Therefore, we used H3K9me2 ChIP-seq to compare its abundance in control and dot-1.1 loss-of-function mutant worms, as well as in rde-4; dot-1.1 and rde-1; dot-1.1 double mutants. The rde-1 and rde-4 genes are components of the RNAi pathway in C. elegans, and RNAi is known to initiate H3K9 methylation in many organisms, including C. elegans. We have previously shown that dot-1.1(−) lethality is rescued by rde-1 and rde-4 loss-of-function. Here we found that H3K9me2 was elevated in enhancer, but not promoter, regions bound by the DOT-1.1/ZFP-1 complex in dot-1.1(−) worms. We also found increased H3K9me2 at genes targeted by the ALG-3/4-dependent small RNAs and repeat regions. Our results suggest that ectopic H3K9me2 in dot-1.1(−) could, in some cases, be induced by small RNAs.

show abstract

Restriction of Cellular Plasticity of Differentiated Cells Mediated by Chromatin Modifiers, Transcription Factors and Protein Kinases

Cited by 28 publications

References 73 publications

The O-GlcNAc transferase OGT is a conserved and essential regulator of the cellular and organismal response to hypertonic stress

The O-GlcNAc transferase OGT is a conserved and essential regulator of the cellular and organismal response to hypertonic stress

TheO-GlcNAc transferase OGT is a conserved and essential regulator of the cellular and organismal response to hypertonic stress

Caenorhabditis elegans Deficient in DOT-1.1 Exhibit Increases in H3K9me2 at Enhancer and Certain RNAi-Regulated Regions

Contact Info

Product

Resources

About