Biology subjects

Uribe, I.

Publications and source records attributed to Uribe, I..

3 recordsLinked to original sources

bioRxiv2024

Global remodeling of ADP-ribosylation by PARP1 suppresses influenza A virus infection

ADP-ribosylation is a highly dynamic and fully reversible post-translational modification performed by poly(ADP-ribose) polymerases (PARPs) that modulates protein function, abundance, localization and turnover. Here we show that influenza A virus infection causes a rapid and dramatic upregulation of global ADP-ribosylation that inhibits viral replication. Mass spectrometry defined for the first time the global ADP-ribosylome during infection, creating an infection-specific profile with almost 4,300 modification sites on [~]1,080 host proteins, as well as over 100 modification sites on viral proteins. Our data indicate that the global increase likely reflects a change in the form of ADP-ribosylation rather than modification of new targets. Functional assays demonstrated that modification of the viral replication machinery antagonizes its activity and further revealed that the anti-viral activity of PARPs and ADP-ribosylation is counteracted by the influenza A virus protein NS1, assigning a new activity to the primary viral antagonist of innate immunity. We identified PARP1 as the enzyme producing the majority of poly(ADP-ribose) present during infection. Influenza A virus replicated faster in cells lacking PARP1, linking PARP1 and ADP-ribosylation to the anti-viral phenotype. Together, these data establish ADP-ribosylation as an anti-viral innate immune-like response to viral infection antagonized by a previously unknown activity of NS1.

microbiology↗

bioRxiv2024

Proteogenomic Reprogramming to a Functional Human Totipotent Stem Cell State via a PARP-DUX4 Regulatory Axis

PARP1 (ARTD1) and Tankyrases (TNKS1/TNKS2; PARP5a/5b) are poly-ADP-ribose polymerases (PARPs) with catalytic and non-catalytic functions that regulate both the genome and proteome during zygotic genome activation (ZGA), totipotent, and pluripotent embryonic stages. Here, we show that primed, conventional human pluripotent stem cells (hPSC) cultured continuously under non-specific TNKS1/TNKS2/PARP1-inhibited chemical naive reversion conditions underwent epigenetic reprogramming to clonal blastomere-like stem cells. TIRN stem cells (TIRN-SC) concurrently expressed hundreds of gene targets of the ZGA-priming pioneer factor DUX4, as well as a panoply of four-cell (4C)-specific (e.g., TPRXL, HOX clusters), eight-cell (8C)-specific (e.g., DUXA, GSC, GATA6), primitive endoderm-specific (e.g., GATA4, SOX17), trophectoderm-specific (e.g., CDX2, TFAP2C), and naive epiblast-specific (e.g., DNMT3L, NANOG, POU5F1(OCT4)) factors; all in a hybrid, combinatorial single-cell manner. Mapping of proteomic and single-cell expressions of TIRN-SC against human preimplantation embryo references identified them as relatively homogenous 4C-8C stage populations. Injection of TIRN cells into murine 8C-16C-staged embryos resulted in efficient totipotent-like single cell contributions of human cells to both extra-embryonic (trophectoderm, placenta) and embryonic (neural, fetal liver, hematopoietic) lineages in human-murine blastocyst and fetal chimeras. Pairing of proteome with ubiquitinome analyses of TIRN-SC revealed a global shutdown of ADP-ribosylation, and a perturbed TNKS/PARP1 equilibrium which not only impacted the protein levels of hundreds of TNKS/PARP1 substrates via a rewiring of the ubiquitin-proteosome system (UPS), but also de-repressed expression of hundreds of developmental genes associated with PARP1 suppression. ChIP-Seq analysis of core NANOG-SOX2-OCT4 (NSO) pluripotency factors in TIRN-SC identified reprogrammed DUX4-accessible distal and cis-regulatory enhancer regions that were co-bound by PARP1 (NSOP). These NSOP enhancer regions possessed co-binding motifs for hundreds of the same ZGA-associated, embryonic, and extraembryonic lineage-specifying pioneer factors (e.g., HOX, FOX, GATA, SOX, TBX, CDX families) that were concurrently co-expressed in TIRN-SC; suggesting that PARP1 and DUX4 cooperate with NSO pluripotency core factors to regulate the epigenetic plasticity of a human totipotency program. These findings provide the first demonstration that global, proteome-wide perturbations of post-translational modifications (i.e., ADP-ribosylation, ubiquitination) can regulate epigenetic reprogramming during human embryogenesis. Totipotent TIRN-SC will provide a valuable cell culture model for studying the proteogenomic regulation of lineage specification from human blastomere stages and may facilitate the efficient generation of human organs in interspecies chimeras.

developmental biology↗

bioRxiv2023

Flap endonuclease 1 repairs DNA-protein crosslinks via ADP-ribosylation

DNA-protein crosslinks (DPCs) are among the most ubiquitous and detrimental DNA lesions which arise from exposure to metabolic stresses, drugs, or crosslinking agents such as formaldehyde (FA). FA is a cellular by-product of methanol metabolism, histone demethylation, lipid peroxidation as well as environmental pollutants. Failure to repair FA-induced DPCs blocks nearly all chromatin-based processes including replication and transcription, leading to immunodeficiencies, neurodegeneration, and cancer. Yet, it remains largely unknown how the cell repairs DPCs. The study of DPC repair is impeded by our incomprehension of the types of proteins crosslinked by FA due to the lack of techniques to identify the DPCs. Here, we designed a novel bioassay to profile FA-induced DPCs by coupling cesium chloride differential ultracentrifugation with HPLC-mass spectrometry (MS). Using the method, we revealed the proteome of FA-induced DPCs in human cells and found that the most abundant proteins that form DPCs are PARP1, topoisomerases I and II, methyltransferases, DNA and RNA polymerases, histones, as well as ribosomal proteins. To identify enzymes that repair DPCs, we carried out RNA interference screening and found that downregulation of flap endonuclease 1 (FEN1) rendered cells hypersensitive to FA. Since FEN1 possesses 5-flap endonuclease activity, we hypothesized that FA induces DPC-conjugated 5-flap DNA fragments that can be processed by FEN1. Indeed, we demonstrate that FA damages DNA bases that are converted into 5-flap via the base excision pathway (BER). We also observed that the damaged DNA bases were colocalized with DPCs and FEN1. Mechanistically, we showed that FEN1 repairs FA-induced DPCs in vivo and cleaves 5-flap DNA substrate harboring DPC mimetic in vitro. We also found that FEN1 repairs enzymatic topoisomerase II (TOP2)-DPCs induced by their inhibitors etoposide and doxorubicin independently of the BER pathway, and that FEN1 and the DPC-targeting protease SPRTN act as parallel pathways for the repair of both FA-induced non-enzymatic DPCs and etoposide-induced enzymatic TOP2-DPCs. Notably, we found that FA-induced non-enzymatic DPCs and enzymatic TOP2-DPCs are promptly modified by poly-ADP-ribosylation (PARylation), a post-translational modification catalyzed by PARP1, a key DNA damage response effector that acts by PARylating both DNA damage sites and DNA repair proteins. We performed immunoprecipitation (IP) assays with anti-PAR antibody for HPLC-MS and identified FEN1 as a PARylation substrate. Next, we showed that PARylation of DPC substrates signaled FEN1 whereas PARylation of FEN1 drove FEN1 to DPC sites. Finally, using the enzymatic labeling of the terminal ADP-ribose-MS method, we identified the E285 residue of FEN1 as a dominant PARylation site, which appeared to be required for FEN1 relocation to DPCs. Taken together, our work not only unveiled the identities of FA-induced DPCs but also discovered an unprecedented PARP1-FEN1 nuclease pathway as a universal and imperative mechanism to repair the miscellaneous DPCs and prevent DPC-induced genomic instability.

molecular biology↗