Project description:Cell cycle progression is linked to transcriptome dynamics and variations in the response of pluripotent cells to differentiation cues, mostly through unknown determinants. Here, we characterized the cell-cycleassociated transcriptome and proteome of mouse embryonic stem cells (mESCs) in naive ground state. We found that the thymine DNA glycosylase (TDG) is a cell-cycle-regulated co-factor of the tumor suppressor p53. Furthermore, TDG and p53 co-bind ESC-specific cis-regulatory elements and thereby control transcription of p53-dependent genes during self-renewal. We determined that the dynamic expression of TDG is required to promote the cell-cycle-associated transcriptional heterogeneity. Moreover, we demonstrated that transient depletion of TDG influences cell fate decisions during the early differentiation of mESCs. Our findings reveal an unanticipated role of TDG in promoting molecular heterogeneity during the cell cycle and highlight the central role of protein dynamics for the temporal control of cell fate during development.
Project description:Cell cycle progression is linked to transcriptome dynamics and variations in the response of pluripotent cells to differentiation cues, through mostly unknown determinants. Here, we characterized the cell cycle–associated transcriptome and proteome of mouse embryonic stem cells (mESCs) in naïve ground state. We found that the thymine DNA glycosylase (TDG) is a cell cycle–regulated co-factor of the tumour suppressor p53. Further, TDG and p53 co-bind ESC-specific cis-regulatory elements and thereby control transcription of p53-dependent genes during self-renewal. We determined that the dynamic expression of TDG is required to promote the cell cycle–associated transcriptional heterogeneity. Moreover, we demonstrated that transient depletion of TDG influences cell fate decisions during the early differentiation of mESCs. Our findings reveal an unanticipated role of TDG in promoting molecular heterogeneity during the cell cycle, and highlight the central role of protein dynamics for the temporal control of cell fate during development.
Project description:The hydrolytic deamination of cytosine and 5-methylcytosine drives many of the transition mutations observed in human cancer. The deamination-induced mutagenic intermediates are either uracil or thymine adducts mispaired with guanine. While a substantial array of methods exists to measure other types of DNA adducts, the cytosine deamination adducts pose unusual analytical problems and adequate methods to measure them have not yet been developed. We describe here a novel hybrid thymine DNA glycosylase, hyTDG, which is comprised of a 29-amino acid sequence from human thymine DNA glycosylase linked to a thymine glycosylase found in an archaeal thermophilic bacterium. Using defined-sequence oligonucleotides, we show that hyTDG has robust mispair-selective activity against deaminated U:G and T:G mispairs. We have further developed a method for separating glycosylase-released free bases from oligonucleotides and DNA followed by GC-MS/MS identification and quantification. Using this approach, we have measured for the first time the levels of total Uracil (U), U:G and T:G in calf thymus DNA. The method presented here will allow the measurement of the formation, persistence, and repair of a biologically important class of deaminated cytosine adducts.
Project description:Thymine DNA Glycosylase (TDG) is a versatile protein involved in DNA mismatch repair, DNA demethylation, and transcriptional regulation. Here, we identify TDG as a synthetic essential effector in p53-deficient tumours. We found that deletion of TDG inhibits cell proliferation specifically in p53-deficient cancer cells. Using a genetically engineered mouse model of lung adenocarcinoma (LUAD), we demonstrate that depletion of TDG suppresses tumour growth in the p53-deficient context. Notably, A novel and selective inhibitor developed to disrupt the DNA binding activity of TDG exhibits therapeutic efficacy against p53-deficient tumours in both cellular and xenograft models. Mechanistically, TDG coordinates with p53 to orchestrate the transcription of RNA helicase DHX9, which functions to eliminate dsRNA. Depletion of TDG in p53-deficient cells results in the downregulation of DHX9 and aberrant cytoplasmic double-strand (dsRNA) accumulation derived from Alu elements, subsequently activating the RIG-I/MDA5-MAVS mediated antiviral response. Moreover, single-cell RNA-sequencing analysis revealed the depletion of TDG in p53-deficient tumours facilitates the recruitment of tumour-infiltrating lymphocytes. We observed that TDG inhibition combined with immune checkpoint blockade (ICB) achieved a strong synergistic anti-tumour effect in p53-deficient tumours. This study highlights the function of TDG in maintaining p53-deficient tumour growth and provides an alternative therapeutic target for p53-deficient cancers.
Project description:Thymine DNA Glycosylase (TDG) is a versatile protein involved in DNA mismatch repair, DNA demethylation, and transcriptional regulation. Here, we identify TDG as a synthetic essential effector in p53-deficient tumours. We found that deletion of TDG inhibits cell proliferation specifically in p53-deficient cancer cells. Using a genetically engineered mouse model of lung adenocarcinoma (LUAD), we demonstrate that depletion of TDG suppresses tumour growth in the p53-deficient context. Notably, A novel and selective inhibitor developed to disrupt the DNA binding activity of TDG exhibits therapeutic efficacy against p53-deficient tumours in both cellular and xenograft models. Mechanistically, TDG coordinates with p53 to orchestrate the transcription of RNA helicase DHX9, which functions to eliminate dsRNA. Depletion of TDG in p53-deficient cells results in the downregulation of DHX9 and aberrant cytoplasmic double-strand (dsRNA) accumulation derived from Alu elements, subsequently activating the RIG-I/MDA5-MAVS mediated antiviral response. Moreover, single-cell RNA-sequencing analysis revealed the depletion of TDG in p53-deficient tumours facilitates the recruitment of tumour-infiltrating lymphocytes. We observed that TDG inhibition combined with immune checkpoint blockade (ICB) achieved a strong synergistic anti-tumour effect in p53-deficient tumours. This study highlights the function of TDG in maintaining p53-deficient tumour growth and provides an alternative therapeutic target for p53-deficient cancers.
Project description:Thymine DNA Glycosylase (TDG) is a versatile protein involved in DNA mismatch repair, DNA demethylation, and transcriptional regulation. Here, we identify TDG as a synthetic essential effector in p53-deficient tumours. We found that deletion of TDG inhibits cell proliferation specifically in p53-deficient cancer cells. Using a genetically engineered mouse model of lung adenocarcinoma (LUAD), we demonstrate that depletion of TDG suppresses tumour growth in the p53-deficient context. Notably, A novel and selective inhibitor developed to disrupt the DNA binding activity of TDG exhibits therapeutic efficacy against p53-deficient tumours in both cellular and xenograft models. Mechanistically, TDG coordinates with p53 to orchestrate the transcription of RNA helicase DHX9, which functions to eliminate dsRNA. Depletion of TDG in p53-deficient cells results in the downregulation of DHX9 and aberrant cytoplasmic double-strand (dsRNA) accumulation derived from Alu elements, subsequently activating the RIG-I/MDA5-MAVS mediated antiviral response. Moreover, single-cell RNA-sequencing analysis revealed the depletion of TDG in p53-deficient tumours facilitates the recruitment of tumour-infiltrating lymphocytes. We observed that TDG inhibition combined with immune checkpoint blockade (ICB) achieved a strong synergistic anti-tumour effect in p53-deficient tumours. This study highlights the function of TDG in maintaining p53-deficient tumour growth and provides an alternative therapeutic target for p53-deficient cancers.
Project description:Thymine DNA Glycosylase (TDG) is a versatile protein involved in DNA mismatch repair, DNA demethylation, and transcriptional regulation. Here, we identify TDG as a synthetic essential effector in p53-deficient tumours. We found that deletion of TDG inhibits cell proliferation specifically in p53-deficient cancer cells. Using a genetically engineered mouse model of lung adenocarcinoma (LUAD), we demonstrate that depletion of TDG suppresses tumour growth in the p53-deficient context. Notably, A novel and selective inhibitor developed to disrupt the DNA binding activity of TDG exhibits therapeutic efficacy against p53-deficient tumours in both cellular and xenograft models. Mechanistically, TDG coordinates with p53 to orchestrate the transcription of RNA helicase DHX9, which functions to eliminate dsRNA. Depletion of TDG in p53-deficient cells results in the downregulation of DHX9 and aberrant cytoplasmic double-strand (dsRNA) accumulation derived from Alu elements, subsequently activating the RIG-I/MDA5-MAVS mediated antiviral response. Moreover, single-cell RNA-sequencing analysis revealed the depletion of TDG in p53-deficient tumours facilitates the recruitment of tumour-infiltrating lymphocytes. We observed that TDG inhibition combined with immune checkpoint blockade (ICB) achieved a strong synergistic anti-tumour effect in p53-deficient tumours. This study highlights the function of TDG in maintaining p53-deficient tumour growth and provides an alternative therapeutic target for p53-deficient cancers.
Project description:Thymine DNA Glycosylase (TDG) is a versatile protein involved in DNA mismatch repair, DNA demethylation, and transcriptional regulation. Here, we identify TDG as a synthetic essential effector in p53-deficient tumours. We found that deletion of TDG inhibits cell proliferation specifically in p53-deficient cancer cells. Using a genetically engineered mouse model of lung adenocarcinoma (LUAD), we demonstrate that depletion of TDG suppresses tumour growth in the p53-deficient context. Notably, A novel and selective inhibitor developed to disrupt the DNA binding activity of TDG exhibits therapeutic efficacy against p53-deficient tumours in both cellular and xenograft models. Mechanistically, TDG coordinates with p53 to orchestrate the transcription of RNA helicase DHX9, which functions to eliminate dsRNA. Depletion of TDG in p53-deficient cells results in the downregulation of DHX9 and aberrant cytoplasmic double-strand (dsRNA) accumulation derived from Alu elements, subsequently activating the RIG-I/MDA5-MAVS mediated antiviral response. Moreover, single-cell RNA-sequencing analysis revealed the depletion of TDG in p53-deficient tumours facilitates the recruitment of tumour-infiltrating lymphocytes. We observed that TDG inhibition combined with immune checkpoint blockade (ICB) achieved a strong synergistic anti-tumour effect in p53-deficient tumours. This study highlights the function of TDG in maintaining p53-deficient tumour growth and provides an alternative therapeutic target for p53-deficient cancers.