Polycomb-dependent breakdown of the intestinal barrier in aging Drosophila
Ontology highlight
ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE291173 | GEO | 2025/11/11
REPOSITORIES: GEO
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Project description:The Polycomb repression machinery in Drosophila comprises PRC1 that monoubiquitinates histone H2A at lysine 118 (H2Aub1) and PR-DUB, a major H2Aub1 deubiquitinase, but how H2Aub1 levels must be balanced for Polycomb repression remains enigmatic. We show that H2Aub1 is enriched at Polycomb target genes in early embryos but depleted from these genes during developmental stages when PRC1 represses their transcription. Accordingly, Polycomb targets remain repressed in H2Aub1-deficient animals. In PR-DUB catalytic mutants, high-level H2Aub1 accumulation at Polycomb targets increases chromatin accessibility, consistent with disruption of chromatin fiber folding by H2Aub1 in vitro. Consequently, PR-DUB mutants show defective Polycomb repression, while general transcription is largely unperturbed by the genome-wide, low-level H2Aub1 increase. Changes in H2Aub1 levels alter H3K27 methylation-kinetics but PRC2 nevertheless generates canonical H3K27me3 domains in PRC1 or PR-DUB catalytic mutants. PR-DUB therefore acts as a rheostat that removes excessive H2Aub1 that, though deposited by PRC1, antagonizes PRC1-mediated chromatin compaction.
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Project description:The Polycomb repression machinery in Drosophila comprises PRC1 that monoubiquitinates histone H2A at lysine 118 (H2Aub1) and PR-DUB, a major H2Aub1 deubiquitinase, but how H2Aub1 levels must be balanced for Polycomb repression remains enigmatic. We show that H2Aub1 is enriched at Polycomb target genes in early embryos but depleted from these genes during developmental stages when PRC1 represses their transcription. Accordingly, Polycomb targets remain repressed in H2Aub1-deficient animals. In PR-DUB catalytic mutants, high-level H2Aub1 accumulation at Polycomb targets increases chromatin accessibility, consistent with disruption of chromatin fiber folding by H2Aub1 in vitro. Consequently, PR-DUB mutants show defective Polycomb repression, while general transcription is largely unperturbed by the genome-wide, low-level H2Aub1 increase. Changes in H2Aub1 levels alter H3K27 methylation-kinetics but PRC2 nevertheless generates canonical H3K27me3 domains in PRC1 or PR-DUB catalytic mutants. PR-DUB therefore acts as a rheostat that removes excessive H2Aub1 that, though deposited by PRC1, antagonizes PRC1-mediated chromatin compaction.
2022-11-09 | GSE210232 | GEO
Project description:The Polycomb repression machinery in Drosophila comprises PRC1 that monoubiquitinates histone H2A at lysine 118 (H2Aub1) and PR-DUB, a major H2Aub1 deubiquitinase, but how H2Aub1 levels must be balanced for Polycomb repression remains enigmatic. We show that H2Aub1 is enriched at Polycomb target genes in early embryos but depleted from these genes during developmental stages when PRC1 represses their transcription. Accordingly, Polycomb targets remain repressed in H2Aub1-deficient animals. In PR-DUB catalytic mutants, high-level H2Aub1 accumulation at Polycomb targets increases chromatin accessibility, consistent with disruption of chromatin fiber folding by H2Aub1 in vitro. Consequently, PR-DUB mutants show defective Polycomb repression, while general transcription is largely unperturbed by the genome-wide, low-level H2Aub1 increase. Changes in H2Aub1 levels alter H3K27 methylation-kinetics but PRC2 nevertheless generates canonical H3K27me3 domains in PRC1 or PR-DUB catalytic mutants. PR-DUB therefore acts as a rheostat that removes excessive H2Aub1 that, though deposited by PRC1, antagonizes PRC1-mediated chromatin compaction.
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Project description:Polycomb-dependent breakdown of the intestinal barrier in aging Drosophila
| PRJNA1232151 | ENA
Project description:This SuperSeries is composed of the following subset Series: GSE24992: Drosophila brain microRNA expression with age: miRNA profiling GSE25007: Drosophila brain gene expression with age: mRNA profiling GSE25008: Drosophila brain gene expression between wildtype and miR-34 null flies Refer to individual Series. Aging is the most prominent risk factor for human neurodegenerative disease, but underlying mechanisms that connect two processes are less well characterized. With age, the brain undergoes functional decline and perhaps degeneration. Such decline may not just contribute to normal aging, but also enhance susceptibility to and progression of age-related neurodegenerative diseases. Therefore, defining intrinsic factors and pathways that underline the normal integrity of the adult nervous system may lead to insights that potentially link aging and neurodegeneration. Here, we report a highly conserved microRNA (miRNA), miR-34, as a modulator of aging and neurodegeneration. Using Drosophila, we show that fly miR-34 expression is brain-enriched and strikingly upregulated with age. Functional studies reveal that, whereas animals without miR-34 are normal as young adults, upon aging, they gradually show late-onset deficits characteristic of accelerated brain aging; these include a transcriptional signature of aged animals, coupled with rapid functional decline, loss of brain integrity, followed by a catastrophic decline in adult viability. Moreover, upregulation of miR-34 protects against neurodegeneration induced by pathogenic human polyglutamine (polyQ) disease protein. We next reveal a dramatic effect of miR-34 to silence the Eip74EF gene of steroid hormone pathways in the adult, which is crucial to maintain the normal aging. Collectively, these data define a miR-34-mediated mechanism that specifically affects long-term integrity of the adult nervous system. miR-34 function in Drosophila may thus present a link that functionally connects aging and neurodegeneration. Our studies implicate essential roles of miRNA- dependent pathways in maintenance of the adult brain, disease pathogenesis and healthy aging.
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Project description:Tissue homeostasis requires long-term lineage fidelity of somatic stem cells. Whether and how age-related changes in somatic stem cells impact the faithful execution of lineage decisions remains largely unknown. Here, we address this question using genome-wide chromatin accessibility and transcriptome analysis as well as single cell RNA-seq to explore stem cell intrinsic changes in the aging Drosophila intestine. These studies indicate that in stem cells of old flies, promoters of Polycomb (Pc) target genes become differentially accessible, resulting in the increased expression of enteroendocrine (EE) cell specification genes. Consistently, we find age related changes in the composition of the EE progenitor cell population in aging intestines, as well as a significant increase in the proportion of EE-specified ISCs and progenitors in aging flies. We further confirm that Pc-mediated chromatin regulation is a critical determinant of EE cell specification in the Drosophila intestine. Pc is required to maintain expression of stem cell genes while ensuring repression of differentiation and specification genes. Our results identify Pc group proteins as central regulators of lineage identity in the intestinal epithelium and highlight the impact of age-related decline in chromatin regulation on tissue homeostasis.
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Project description:Tissue homeostasis requires long-term lineage fidelity of somatic stem cells. Whether and how age-related changes in somatic stem cells impact the faithful execution of lineage decisions remains largely unknown. Here, we address this question using genome-wide chromatin accessibility and transcriptome analysis as well as single cell RNA-seq to explore stem cell-intrinsic changes in the aging Drosophila intestine. These studies indicate that in stem cells of old flies, promoters of Polycomb (Pc) target genes become differentially accessible, resulting in the increased expression of enteroendocrine (EE) cell specification genes. Consistently, we find age-related changes in the composition of the EE progenitor cell population in aging intestines, as well as a significant increase in the proportion of EE-specified ISCs and progenitors in aging flies. We further confirm that Pc-mediated chromatin regulation is a critical determinant of EE cell specification in the Drosophila intestine. Pc is required to maintain expression of stem cell genes while ensuring repression of differentiation and specification genes. Our results identify Pc group proteins as central regulators of lineage identity in the intestinal epithelium and highlight the impact of age-related decline in chromatin regulation on tissue homeostasis.
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Project description:Tissue homeostasis requires long-term lineage fidelity of somatic stem cells. Whether and how age-related changes in somatic stem cells impact the faithful execution of lineage decisions remains largely unknown. Here, we address this question using genome-wide chromatin accessibility and transcriptome analysis as well as single cell RNA-seq to explore stem cell intrinsic changes in the aging Drosophila intestine. These studies indicate that in stem cells of old flies, promoters of Polycomb (Pc) target genes become differentially accessible, resulting in the increased expression of enteroendocrine (EE) cell specification genes. Consistently, we find age related changes in the composition of the EE progenitor cell population in aging intestines, as well as a significant increase in the proportion of EE-specified ISCs and progenitors in aging flies. We further confirm that Pc-mediated chromatin regulation is a critical determinant of EE cell specification in the Drosophila intestine. Pc is required to maintain expression of stem cell genes while ensuring repression of differentiation and specification genes. Our results identify Pc group proteins as central regulators of lineage identity in the intestinal epithelium and highlight the impact of age-related decline in chromatin regulation on tissue homeostasis.
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Project description:Tissue homeostasis requires long-term lineage fidelity of somatic stem cells. Whether and how age-related changes in somatic stem cells impact the faithful execution of lineage decisions remains largely unknown. Here, we address this question using genome-wide chromatin accessibility and transcriptome analysis as well as single cell RNA-seq to explore stem cell intrinsic changes in the aging Drosophila intestine. These studies indicate that in stem cells of old flies, promoters of Polycomb (Pc) target genes become differentially accessible, resulting in the increased expression of enteroendocrine (EE) cell specification genes. Consistently, we find age related changes in the composition of the EE progenitor cell population in aging intestines, as well as a significant increase in the proportion of EE-specified ISCs and progenitors in aging flies. We further confirm that Pc-mediated chromatin regulation is a critical determinant of EE cell specification in the Drosophila intestine. Pc is required to maintain expression of stem cell genes while ensuring repression of differentiation and specification genes. Our results identify Pc group proteins as central regulators of lineage identity in the intestinal epithelium and highlight the impact of age-related decline in chromatin regulation on tissue homeostasis.
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