Browsing by Subject "Nucleotides"

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    Differential labelling of UDP-N-acetylglucosamine in Huntington's-chorea fibroblasts.
    (Biochem J, 1981-05-15) Hung, WY; Tourian, A
    The hypothesis that there is impaired endogenous synthesis of glucosamine 6-phosphate in Huntington's-chorea fibroblasts was tested by double labelling matched pairs of fibroblasts in culture with carrier-free H3 32PO4 and [U-14C]glucosamine. The [32P]UDP-N-acetyl[14C]glucosamine and [14C]glucosamine 6-[32P]phosphate of the cellular soluble fraction was isolated by charcoal column and paper chromatography. There is no quantitative difference in 32P but a significant difference in 14C in these two sugars in a ratio of approx. 1.5 for Huntington's-chorea fibroblasts compared with normal fibroblasts.
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    Interspecies Papillomavirus Type Infection and a Novel Papillomavirus Type in Red Ruffed Lemurs (Varecia rubra).
    (Viruses, 2023-12) Paietta, Elise N; Kraberger, Simona; Regney, Melanie; Custer, Joy M; Ehmke, Erin; Yoder, Anne D; Varsani, Arvind
    The Papillomaviridae are a family of vertebrate-infecting viruses of oncogenic potential generally thought to be host species- and tissue-specific. Despite their phylogenetic relatedness to humans, there is a scarcity of data on papillomaviruses (PVs) in speciose non-human primate lineages, particularly the lemuriform primates. Varecia variegata (black-and-white ruffed lemurs) and Varecia rubra (red ruffed lemurs), two closely related species comprising the Varecia genus, are critically endangered with large global captive populations. Varecia variegata papillomavirus (VavPV) types -1 and -2, the first PVs in lemurs with a fully identified genome, were previously characterized from captive V. variegata saliva. To build upon this discovery, saliva samples were collected from captive V. rubra with the following aims: (1) to identify PVs shared between V. variegata and V. rubra and (2) to characterize novel PVs in V. rubra to better understand PV diversity in the lemuriform primates. Three complete PV genomes were determined from V. rubra samples. Two of these PV genomes share 98% L1 nucleotide identity with VavPV2, denoting interspecies infection of V. rubra by VavPV2. This work represents the first reported case of interspecies PV infection amongst the strepsirrhine primates. The third PV genome shares <68% L1 nucleotide identity with that of all PVs. Thus, it represents a new PV species and has been named Varecia rubra papillomavirus 1 (VarPV1). VavPV1, VavPV2, and VarPV1 form a new clade within the Papillomaviridae family, likely representing a novel genus. Future work diversifying sample collection (i.e., lemur host species from multiple genera, sample type, geographic location, and wild populations) is likely to uncover a world of diverse lemur PVs.
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    Phosphorylation of guanosine monophosphate reductase triggers a GTP-dependent switch from pro- to anti-oncogenic function of EPHA4.
    (Cell chemical biology, 2022-06) Wolff, David W; Deng, Zhiyong; Bianchi-Smiraglia, Anna; Foley, Colleen E; Han, Zhannan; Wang, Xingyou; Shen, Shichen; Rosenberg, Masha M; Moparthy, Sudha; Yun, Dong Hyun; Chen, Jialin; Baker, Brian K; Roll, Matthew V; Magiera, Andrew J; Li, Jun; Hurley, Edward; Feltri, Maria Laura; Cox, Anderson O; Lee, Jingyun; Furdui, Cristina M; Liu, Liang; Bshara, Wiam; LaConte, Leslie EW; Kandel, Eugene S; Pasquale, Elena B; Qu, Jun; Hedstrom, Lizbeth; Nikiforov, Mikhail A
    Signal transduction pathways post-translationally regulating nucleotide metabolism remain largely unknown. Guanosine monophosphate reductase (GMPR) is a nucleotide metabolism enzyme that decreases GTP pools by converting GMP to IMP. We observed that phosphorylation of GMPR at Tyr267 is critical for its activity and found that this phosphorylation by ephrin receptor tyrosine kinase EPHA4 decreases GTP pools in cell protrusions and levels of GTP-bound RAC1. EPHs possess oncogenic and tumor-suppressor activities, although the mechanisms underlying switches between these two modes are poorly understood. We demonstrated that GMPR plays a key role in EPHA4-mediated RAC1 suppression. This supersedes GMPR-independent activation of RAC1 by EPHA4, resulting in a negative overall effect on melanoma cell invasion and tumorigenicity. Accordingly, EPHA4 levels increase during melanoma progression and inversely correlate with GMPR levels in individual melanoma tumors. Therefore, phosphorylation of GMPR at Tyr267 is a metabolic signal transduction switch controlling GTP biosynthesis and transformed phenotypes.
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    RIPK3: Beyond Necroptosis.
    (Immunity, 2019-01) Evans, Azia S; Coyne, Carolyn B
    In this issue of Immunity, Daniels et al. (2019) demonstrate that RIPK3 signaling limits Zika virus (ZIKV) infection in the central nervous system independently of its function in necroptosis by promoting itaconate production in infected neurons, thereby revealing a neuron-specific mechanism of metabolite-mediated ZIKV control.