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Tabach, Y.

Publications and source records attributed to Tabach, Y..

8 recordsLinked to original sources

Analysis of genes co-evolved with Igf2bp RNA-Binding Proteins provides insights into post-transcriptional regulatory networks

The Insulin-like growth factor 2 mRNA-binding protein (Igf2bp) family comprises three paralogous RNA-binding proteins--Igf2bp1, Igf2bp2, and Igf2bp3--that are highly conserved across chordates. Originally identified through diverse experimental screens probing intracellular RNA localization, RNA stability, and translational control, Igf2bps were initially studied in isolation from one another and within narrowly defined molecular contexts. Over time, it has become clear that these proteins act as multifunctional regulators of RNA metabolism and participate in a broad range of developmental and pathological processes. Here, we review the discovery, molecular functions, and biological roles of Igf2bp proteins, with particular emphasis on their conserved involvement in nervous system development and their reactivation in cancer. Given the emerging appreciation of the connection between genes involved in neural development and tumorigenesis, we thought it might be informative to perform a comparative evolutionary analysis to identify genes that coevolved with Igf2bp paralogs. These coevolved genes are strongly enriched for functions in axon guidance and neurogenesis, but also substantially overlap with experimentally defined Igf2bp1 RNA targets in lung adenocarcinoma (LUAD) cells. Notably, many of these genes are downregulated upon pharmacological inhibition of Igf2bp1 RNA binding. In this speculative review, we propose a model in which Igf2bp proteins evolved as coordinators of post-transcriptional gene regulation in the developing nervous system and were later co-opted in cancer to stabilize and coordinate oncogenic gene expression programs.

molecular biology↗

CladeOScope-GSA: A Tool for Predicting Functional Gene Interactions via Phylogenetic Profiling

Understanding gene function and protein network dynamics is a key challenge in biology and human health. In the light of the exponential growth in genomic data, phylogenetic profiling methods became more powerful in analysing thousands of genomes to uncover evolutionary associations and predict functional interactions [1,2,4,13,14,16,18,23,24,26]. It is based on the well-supported hypothesis that genes that work together are subject to similar evolutionary pressures and therefore their conservation patterns across phylogeny are correlated. We introduce CladeOScope-GSA, a web-based tool designed for phylogeny-aware analysis of gene sets across extensive comparative genomics datasets. By integrating clade-focused normalized phylogenetic profiling (NPP) with interactive visualization, CladeOScope-GSA enables researchers to identify evolutionary patterns within user-defined gene sets. Building upon the infrastructure of the original CladeOScope visualization platform, the addition of statistical gene set analysis, expanded phylogenetic and genomic data, enhanced visualization, and improved statistical tools represent a significant advancement in the tools capabilities. We demonstrate its utility through case studies spanning 1905 species, showcasing how CladeOScope-GSA empowers researchers to extract biological insights from complex comparative datasets. The web tool is accessible at https://tabachlab.shinyapps.io/CladeOScope

evolutionary biology↗

Cross-species identification of cancer-resistance associated genes uncovers their relevance to human cancer risk

Cancer is an evolutionarily conserved disease that occurs in a wide variety of species. We applied a comparative genomics approach to systematically characterize the genes whose conservation levels significantly correlates positively (PC) or negatively (NC) with a broad spectrum of cancer-resistance estimates, computed across almost 200 vertebrate species. PC genes are enriched in pathways relevant to tumor suppression including cell cycle, DNA repair, and immune response, while NC genes are enriched with a host of metabolic pathways. The conservation levels of the PC and NC genes in a species serve to build the first genomics-based predictor of its cancer resistance score. We find that PC genes are less tolerant to loss of function (LoF) mutations, are enriched in cancer driver genes and are associated with germline mutations that increase human cancer risk. Furthermore, their expression levels are associated with lifetime cancer risk across human tissues. Finally, their knockout in mice results in increased cancer incidence. In sum, we find that many genes associated with cancer resistance across species are implicated in human cancers, pointing to several additional candidate genes that may have a functional role in human cancer.

cancer biology↗

RNA interference mediates RNA toxicity with parent-of-origin effects in C. elegans expressing CTG repeats

Nucleotide repeat expansions are a hallmark of over 40 neurodegenerative diseases. These repeats cause RNA toxicity and trigger multisystemic symptoms that worsen with age. RNA toxicity can trigger, through an unclear mechanism, severe disease manifestation in infants that inherited repeats from their mothers. Here we show in Caenorhabditis elegans how RNA interference machinery causes intergenerational toxicity through inheritance of siRNAs derived from CUG repeats. The maternal repeat-derived small RNAs cause transcriptomic changes in the offspring, reduce motility and shorten lifespan. However, the toxicity phenotypes in the offspring can be rescued by perturbing the RNAi machinery in affected mothers. This points to a novel mechanism linking maternal bias and the RNAi machinery and suggests that toxic RNA is transmitted to offspring and causes disease phenotypes through intergenerational epigenetic inheritance.

molecular biology↗

Expanding the MECP2 network using comparative genomics reveals potential therapeutic targets for Rett syndrome

Inactivating mutations in the Methyl-CpG Binding Protein 2 (MECP2) gene are the main cause of Rett syndrome (RTT). Despite extensive research into MECP2 function, no treatments for RTT are currently available. Here we use an evolutionary genomics approach to construct an unbiased MECP2 gene network, using 1,028 eukaryotic genomes to prioritize proteins with strong co-evolutionary signatures with MECP2. Focusing on proteins targeted by FDA approved drugs led to three promising candidates, two of which were previously linked to MECP2 function (IRAK, KEAP1) and one that was not (EPOR). We show that each of these compounds has the ability to rescue different phenotypes of MECP2 inactivation in cultured human neural cell types, and appear to act on Nuclear Factor Kappa B (NF-{kappa}B) signaling in inflammation. This study highlights the potential of comparative genomics to accelerate drug discovery, and yields potential new avenues for the treatment of RTT. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/431162v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1d7e0f8org.highwire.dtl.DTLVardef@1f2c602org.highwire.dtl.DTLVardef@1a5dd7dorg.highwire.dtl.DTLVardef@7071c8_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

Alternative splicing of SLAMF6 in human T cells creates a co-stimulatory isoform that counteracts the inhibitory effect of the full-length receptor

SLAMF6 is a homotypic receptor of the Ig-superfamily associated with progenitor exhausted T cells. In humans, SLAMF6 has three splice isoforms involving its V-domain. While the canonical 8-exon receptor inhibits T cell activation through SAP recruitment, the short isoform SLAMF6{Delta}17-65 has a strong agonistic effect. The costimulatory action depends on protein phosphatase SHP-1 and leads to a cytotoxic molecular profile governed by transcription factors Tbet, Runx3, and Tcf7. In T cells from individual patients treated with immune checkpoint blockade, a shift was noted towards SLAMF6{Delta}17-65. Splice-switching antisense oligonucleotides designed to target the SLAMF6 splice junction, enhanced SLAMF6{Delta}17-65 in human tumor-infiltrating lymphocytes and improved their capacity to inhibit human melanoma in mice. The possible emergence of two opposing isoforms from the SLAMF6 gene may represent an immune-modulatory mechanism that can be exploited for cancer immunotherapy.

immunology↗

Conservation motifs - a novel evolutionary-based classification of proteins

Cross-species protein conservation patterns, as directed by natural selection, are indicative of the interplay between protein function, protein-protein interaction and evolution. Since the beginning of the genomic era, proteins were characterized as either conserved or not conserved. This simple classification became archaic and cursory once data on protein orthologs became available for thousands of species. To enrich the language used to describe protein conservation patterns, and to understand their biological significance, we classified 20,294 human proteins against 1096 species. Analyses of the conservation patterns of human proteins in different eukaryotic clades yielded extremely variable and rich patterns that had never been characterized or studied before. Using mathematical classifications, we defined seven conservation motifs: Steps, Critical, Lately Developed, Plateau, Clade Loss, Trait Loss and Gain, which describe the evolution of human proteins. Overall, our work offers novel terms for conservation patterns and defines a new language intended to comprehensively describe protein evolution. This novel terminology enables the classification of proteins based on evolution, reveals aspects of protein evolution, and improves the understanding of protein functions.

evolutionary biology↗

FAM35A co-operates with REV7 to coordinate DNA double-strand break repair pathway choice.

DNA double-strand breaks (DSBs) can be repaired by two major pathways: non-homologous end-joining (NHEJ) and homologous recombination (HR). DNA repair pathway choice is governed by the opposing activities of 53BP1, in complex with its effectors RIF1 and REV7, and BRCA1. However, it remains unknown how the 53BP1/RIF1/REV7 complex stimulates NHEJ and restricts HR to the S/G2 phases of the cell cycle. Using a mass spectrometry (MS)-based approach, we identify 11 high-confidence REV7 interactors and elucidate the role of a previously undescribed factor, FAM35A/SHDL2, as a novel effector of REV7 in the NHEJ pathway. FAM35A depletion impairs NHEJ-mediated DNA repair and compromises antibody diversification by class switch recombination (CSR) in B-cells. FAM35A accumulates at DSBs in a 53BP1-, RIF1- and REV7-dependent manner and antagonizes HR by limiting DNA end resection. In fact, FAM35A is part of a larger complex composed of REV7 and another previously uncharacterized protein, C20orf196/SHDL1, which promotes NHEJ and limits HR. Together, these results establish FAM35A as a novel effector of REV7 in controlling the decision-making process during DSB repair.

cancer biology↗