Publications by authors named "Abigael Cheruiyot"

Article Synopsis
  • Keeping the replication fork safe during stress is super important for preventing cancer and keeping our DNA stable.!
  • A signaling pathway using TRPV2 helps to release calcium, which is important for protecting the replication fork when DNA is damaged or stressed.!
  • Scientists found that a factor called TCAF1 helps TRPV2 work better, which is key for cell survival and DNA stability during tough times.!
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Pancreatic β cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair β cell insulin secretion and have been shown experimentally to suppress insulin translation.

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Pancreatic β-cells are specialized for coupling glucose metabolism to insulin peptide production and secretion. Acute glucose exposure robustly and coordinately increases translation of proinsulin and proteins required for secretion of mature insulin peptide. By contrast, chronically elevated glucose levels that occur during diabetes impair β-cell insulin secretion and have been shown experimentally to suppress insulin translation.

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The protection of DNA replication forks under stress is essential for genome maintenance and cancer suppression. One mechanism of fork protection involves an elevation in intracellular Ca ([Ca]), which in turn activates CaMKK2 and AMPK to prevent uncontrolled fork processing by Exo1. How replication stress triggers [Ca] elevation is unclear.

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Uncontrolled resection of replication forks under stress can cause genomic instability and influence cancer formation. Extensive fork resection has also been implicated in the chemosensitivity of "BReast CAncer gene" BRCA-deficient cancers. However, how fork resection is controlled in different genetic contexts and how it affects chromosomal stability and cell survival remains incompletely understood.

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Article Synopsis
  • Nonsense-mediated RNA decay (NMD) is an essential process that degrades faulty mRNAs but its exact mechanisms and implications in health and disease are still being explored.
  • A new reporter system and genome-wide CRISPR-Cas9 screening revealed several factors that promote NMD, particularly components of the SF3B complex related to RNA splicing, and highlighted reduced NMD activity in certain cancer-related mutations.
  • The study suggests that targeting the NMD pathway could be a promising therapy for myelodysplastic syndromes and cancers with spliceosome mutations, as enhancing RNase H1 levels can help counteract the negative effects of these mutations.
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The nonsense mediated RNA decay (NMD) pathway safeguards the integrity of the transcriptome by targeting mRNAs with premature translation termination codons (PTCs) for degradation. It also regulates gene expression by degrading a large number of non-mutant RNAs (including mRNAs and noncoding RNAs) that bear NMD-inducing features. Consequently, NMD has been shown to influence development, cellular response to stress, and clinical outcome of many genetic diseases.

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Persistent DNA damage induces profound alterations in gene expression that, in turn, influence tissue homeostasis, tumorigenesis, and cancer treatment outcome. However, the underlying mechanism for gene expression reprogramming induced by persistent DNA damage remains poorly understood. Here, using a highly effective bioluminescence-based reporter system and other tools, we report that persistent DNA damage inhibits nonsense-mediated RNA decay (NMD), an RNA surveillance and gene-regulatory pathway, in noncycling cells.

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Dynamic regulation of RNF168-mediated ubiquitylation of histone H2A Lys13,15 (H2AK13,15ub) at DNA double-strand breaks (DSBs) is crucial for preventing aberrant DNA repair and maintaining genome stability. However, it remains unclear which deubiquitylating enzyme (DUB) removes H2AK13,15ub. Here we show that USP51, a previously uncharacterized DUB, deubiquitylates H2AK13,15ub and regulates DNA damage response.

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Exonuclease 1 (Exo1) has important roles in DNA metabolic transactions that are essential for genome maintenance, telomere regulation and cancer suppression. However, the mechanisms for regulating Exo1 activity in these processes remain incompletely understood. Here, we report that Exo1 activity is regulated by a direct interaction with poly(ADP-ribose) (PAR), a prominent posttranslational modification at the sites of DNA damage.

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Endosomal sorting complexes required for transport (ESCRTs) mediate sorting of ubiquitinated membrane proteins into multivesicular bodies en route to lysosomes for degradation. A mutation in CHMP2B (CHMP2B(Intron5), an ESCRT-III component) that is associated with a hereditary form of frontotemporal dementia (FTD3) disrupts the endosomal-lysosomal pathway and causes accumulation of autophagosomes and multilamellar structures. We previously demonstrated that expression of CHMP2B(Intron5) in the Drosophila eye using GMR-Gal4 causes misregulation of the Toll receptor pathway.

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