scholarly journals Caenorhabditis elegans establishes germline versus soma by balancing inherited histone methylation

Development ◽  
2021 ◽  
Vol 148 (3) ◽  
pp. dev196600 ◽  
Author(s):  
Brandon S. Carpenter ◽  
Teresa W. Lee ◽  
Caroline F. Plott ◽  
Juan D. Rodriguez ◽  
Jovan S. Brockett ◽  
...  

ABSTRACTFormation of a zygote is coupled with extensive epigenetic reprogramming to enable appropriate inheritance of histone methylation and prevent developmental delays. In Caenorhabditis elegans, this reprogramming is mediated by the H3K4me2 demethylase SPR-5 and the H3K9 methyltransferase, MET-2. In contrast, the H3K36 methyltransferase MES-4 maintains H3K36me2/3 at germline genes between generations to facilitate re-establishment of the germline. To determine whether the MES-4 germline inheritance pathway antagonizes spr-5; met-2 reprogramming, we examined the interaction between these two pathways. We found that the developmental delay of spr-5; met-2 mutant progeny is associated with ectopic H3K36me3 and the ectopic expression of MES-4-targeted germline genes in somatic tissues. Furthermore, the developmental delay is dependent upon MES-4 and the H3K4 methyltransferase, SET-2. We propose that MES-4 prevents crucial germline genes from being repressed by antagonizing maternal spr-5; met-2 reprogramming. Thus, the balance of inherited histone modifications is necessary to distinguish germline versus soma and prevent developmental delay.This article has an associated ‘The people behind the papers’ interview.

2020 ◽  
Author(s):  
Brandon S. Carpenter ◽  
Teresa W. Lee ◽  
Caroline F. Plott ◽  
Jovan S. Brockett ◽  
Dexter A. Myrick ◽  
...  

ABSTRACTEmbryos undergo extensive reprogramming at fertilization to prevent the inappropriate inheritance of histone methylation. In C. elegans, this reprogramming is mediated by the H3K4me2 demethylase, SPR-5, and the H3K9 methyltransferase, MET-2. In contrast to this reprogramming, the H3K36 methyltransferase, MES-4, maintains H3K36me2/3 at germline genes between generations to help re-establish the germline. To determine whether the MES-4 germline inheritance system antagonizes spr-5; met-2 reprogramming, we examined the interaction between these two systems. We find that the developmental delay of spr-5; met-2 mutant progeny is associated with ectopic H3K36me2/3 and the ectopic expression of MES-4 targeted germline genes in somatic tissues. Furthermore, the developmental delay is dependent upon MES-4 and the H3K4 methyltransferase, SET-2. We propose that the MES-4 inheritance system prevents critical germline genes from being repressed by maternal spr-5; met-2 reprogramming. Thus, the balance of inherited histone modifications is necessary to distinguish germline versus soma and prevent developmental delay.


Development ◽  
2021 ◽  
Vol 148 (3) ◽  
pp. dev199456

ABSTRACTA dynamic pattern of histone methylation and demethylation controls gene expression during development, with some processes such as formation of the zygote involving large-scale reprogramming of methylation states. A new paper in Development investigates how inherited histone methylation regulates developmental timing and the germline/soma distinction in Caenorhabditis elegans. To hear more about the story we caught up with first author and postdoctoral researcher Brandon Carpenter, and his supervisor David Katz, Associate Professor in the Department of Cell Biology at Emory University School of Medicine in Atlanta, Georgia.


2019 ◽  
Vol 10 (2) ◽  
pp. 863-874
Author(s):  
Jerrin R. Cherian ◽  
Katherine V. Adams ◽  
Lisa N. Petrella

Establishment and maintenance of proper gene expression is a requirement for normal growth and development. The DREAM complex in Caenorhabditis elegans functions as a transcriptional repressor of germline genes in somatic cells. At 26°, DREAM complex mutants show increased misexpression of germline genes in somatic cells and High Temperature Arrest (HTA) of worms at the first larval stage. To identify transcription factors required for the ectopic expression of germline genes in DREAM complex mutants, we conducted an RNA interference screen against 123 transcription factors capable of binding DREAM target promoter loci for suppression of the HTA phenotype in lin-54 mutants. We found that knock-down of 15 embryonically expressed transcription factors suppress the HTA phenotype in lin-54 mutants. Five of the transcription factors found in the initial screen have associations with Wnt signaling pathways. In a subsequent RNAi suppression screen of Wnt signaling factors we found that knock-down of the non-canonical Wnt/PCP pathway factors vang-1, prkl-1 and fmi-1 in a lin-54 mutant background resulted in strong suppression of the HTA phenotype. Animals mutant for both lin-54 and vang-1 showed almost complete suppression of the HTA phenotype, pgl-1 misexpression, and fertility defects associated with lin-54 single mutants at 26°. We propose a model whereby a set of embryonically expressed transcription factors, and the Wnt/PCP pathway, act opportunistically to activate DREAM complex target genes in somatic cells of DREAM complex mutants at 26°.


Genetics ◽  
2019 ◽  
Vol 212 (1) ◽  
pp. 125-140 ◽  
Author(s):  
Andreas Rechtsteiner ◽  
Meghan E. Costello ◽  
Thea A. Egelhofer ◽  
Jacob M. Garrigues ◽  
Susan Strome ◽  
...  

2018 ◽  
Author(s):  
Andreas Rechtsteiner ◽  
Meghan E. Costello ◽  
Thea A. Egelhofer ◽  
Jacob M. Garrigues ◽  
Susan Strome ◽  
...  

Repression of germline-promoting genes in somatic cells is critical for somatic development and function. To study how germline genes are repressed in somatic tissues, we analyzed key histone modifications in three Caenorhabditis elegans synMuv B mutants, lin-15B, lin-35, and lin-37, all of which display ectopic expression of germline genes in the soma. LIN-35 and LIN-37 are members of the conserved DREAM complex. LIN-15B has been proposed to work with the DREAM complex but has not been shown biochemically to be a complex member. We found that in wild-type worms synMuv B target genes and germline genes are enriched for the repressive histone modification dimethylation of histone H3 on lysine 9 (H3K9me2) at their promoters. Genes with H3K9me2 promoter localization are distributed across the autosomes and not biased toward autosomal arms like broad H3K9me2 domains. Both synMuv B targets and germline genes display dramatic reduction of H3K9me2 promoter localization in lin-15B mutants, but much weaker reduction in lin-35 and lin-37 mutants. This is the first major difference reported between lin-15B and DREAM complex mutants, which likely represents a difference in molecular function for these synMuv B proteins. In support of the pivotal role of H3K9me2 in regulation of germline genes through LIN-15B, global loss of H3K9me2 but not H3K9me3 results in phenotypes similar to synMuv B mutants, high temperature larval arrest and ectopic expression of germline genes in the soma. We propose that LIN-15B-driven enrichment of H3K9me2 on promoters of germline genes contributes to repression of those genes in somatic tissues.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jessica Knox ◽  
Nicolas Joly ◽  
Edmond M. Linossi ◽  
José A. Carmona-Negrón ◽  
Natalia Jura ◽  
...  

AbstractOver one billion people are currently infected with a parasitic nematode. Symptoms can include anemia, malnutrition, developmental delay, and in severe cases, death. Resistance is emerging to the anthelmintics currently used to treat nematode infection, prompting the need to develop new anthelmintics. Towards this end, we identified a set of kinases that may be targeted in a nematode-selective manner. We first screened 2040 inhibitors of vertebrate kinases for those that impair the model nematode Caenorhabditis elegans. By determining whether the terminal phenotype induced by each kinase inhibitor matched that of the predicted target mutant in C. elegans, we identified 17 druggable nematode kinase targets. Of these, we found that nematode EGFR, MEK1, and PLK1 kinases have diverged from vertebrates within their drug-binding pocket. For each of these targets, we identified small molecule scaffolds that may be further modified to develop nematode-selective inhibitors. Nematode EGFR, MEK1, and PLK1 therefore represent key targets for the development of new anthelmintic medicines.


Genetics ◽  
1999 ◽  
Vol 151 (1) ◽  
pp. 131-141
Author(s):  
Laurent Molin ◽  
Heinke Schnabel ◽  
Titus Kaletta ◽  
Richard Feichtinger ◽  
Ian A Hope ◽  
...  

Abstract In the early Caenorhabditis elegans embryo five somatic founder cells are born during the first cleavages. The first of these founder cells, named AB, gives rise to 389 of the 558 nuclei present in the hatching larva. Very few genes directly involved in the specification of the AB lineage have been identified so far. Here we describe a screen of a large collection of maternal-effect embryonic lethal mutations for their effect on the early expression of a pes-1::lacZ fusion gene. This fusion gene is expressed in a characteristic pattern in 14 of the 32 AB descendants present shortly after the initiation of gastrulation. Of the 37 mutations in 36 genes suspected to be required specifically during development, 12 alter the expression of the pes-1::lacZ marker construct. The gene expression pattern alterations are of four types: reduction of expression, variable expression, ectopic expression in addition to the normal pattern, and reduction of the normal pattern together with ectopic expression. We estimate that ∼100 maternal functions are required to establish the pes-1 expression pattern in the early embryo.


2018 ◽  
Vol 50 (4) ◽  
pp. 1376-1397 ◽  
Author(s):  
Yanhui Zhai ◽  
Zhiren Zhang ◽  
Hao Yu ◽  
Li Su ◽  
Gang Yao ◽  
...  

Background/Aims: DNA methylation and histone modifications are essential epigenetic marks that can significantly affect the mammalian somatic cell nuclear transfer (SCNT) embryo development. However, the mechanisms by which the DNA methylation affects the epigenetic reprogramming have not been fully elucidated. Methods: In our study, we used quantitative polymerase chain reaction (qPCR), Western blotting, immunofluorescence staining (IF) and sodium bisulfite genomic sequencing to examine the effects of RG108, a DNA methyltransferase inhibitor (DNMTi), on the dynamic pattern of DNA methylation and histone modifications in porcine SCNT embryos and investigate the mechanism by which the epigenome status of donor cells’ affects SCNT embryos development and the crosstalk between epigenetic signals. Results: Our results showed that active DNA demethylation was enhanced by the significantly improving expression levels of TET1, TET2, TET3 and 5hmC, and passive DNA demethylation was promoted by the remarkably inhibitory expression levels of DNMT1, DNMT3A and 5mC in embryos constructed from the fetal fibroblasts (FFs) treated with RG108 (RG-SCNT embryos) compared to the levels in embryos from control FFs (FF-SCNT embryos). The signal intensity of histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 9 acetylation (H3K9Ac) was significantly increased and the expression levels of H3K4 methyltransferases were more than 2-fold higher expression in RG-SCNT embryos. RG-SCNT embryos had significantly higher cleavage and blastocyst rates (69.3±1.4%, and 24.72±2.3%, respectively) than FF-SCNT embryos (60.1±2.4% and 18.38±1.9%, respectively). Conclusion: Dynamic changes in DNA methylation caused by RG108 result in dynamic alterations in the patterns of H3K4me3, H3K9Ac and histone H3 lysine 9 trimethylation (H3K9me3), which leads to the activation of embryonic genome and epigenetic modification enzymes associated with H3K4 methylation, and contributes to reconstructing normal epigenetic modifications and improving the developmental efficiency of porcine SCNT embryos.


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