Browsing by Subject "GENE"

Now showing 1 - 4 of 4
  • Thumbnail Image
    ItemOpen Access
    Comparison of the molecular properties of retinitis pigmentosa P23H and N15S amino acid replacements in rhodopsin.
    (PloS one, 2019-01) Mitchell, James; Balem, Fernanda; Tirupula, Kalyan; Man, David; Dhiman, Harpreet Kaur; Yanamala, Naveena; Ollesch, Julian; Planas-Iglesias, Joan; Jennings, Barbara J; Gerwert, Klaus; Iannaccone, Alessandro; Klein-Seetharaman, Judith
    Mutations in the RHO gene encoding for the visual pigment protein, rhodopsin, are among the most common cause of autosomal dominant retinitis pigmentosa (ADRP). Previous studies of ADRP mutations in different domains of rhodopsin have indicated that changes that lead to more instability in rhodopsin structure are responsible for more severe disease in patients. Here, we further test this hypothesis by comparing side-by-side and therefore quantitatively two RHO mutations, N15S and P23H, both located in the N-terminal intradiscal domain. The in vitro biochemical properties of these two rhodopsin proteins, expressed in stably transfected tetracycline-inducible HEK293S cells, their UV-visible absorption, their Fourier transform infrared, circular dichroism and Metarhodopsin II fluorescence spectroscopy properties were characterized. As compared to the severely impaired P23H molecular function, N15S is only slightly defective in structure and stability. We propose that the molecular basis for these structural differences lies in the greater distance of the N15 residue as compared to P23 with respect to the predicted rhodopsin folding core. As described previously for WT rhodopsin, addition of the cytoplasmic allosteric modulator chlorin e6 stabilizes especially the P23H protein, suggesting that chlorin e6 may be generally beneficial in the rescue of those ADRP rhodopsin proteins whose stability is affected by amino acid replacement.
  • Thumbnail Image
    ItemOpen Access
    Macrophage cells secrete factors including LRP1 that orchestrate the rejuvenation of bone repair in mice.
    (Nature communications, 2018-12-05) Vi, Linda; Baht, Gurpreet S; Soderblom, Erik J; Whetstone, Heather; Wei, Qingxia; Furman, Bridgette; Puviindran, Vijitha; Nadesan, Puviindran; Foster, Matthew; Poon, Raymond; White, James P; Yahara, Yasuhito; Ng, Adeline; Barrientos, Tomasa; Grynpas, Marc; Mosely, M Arthur; Alman, Benjamin A
    The pace of repair declines with age and, while exposure to a young circulation can rejuvenate fracture repair, the cell types and factors responsible for rejuvenation are unknown. Here we report that young macrophage cells produce factors that promote osteoblast differentiation of old bone marrow stromal cells. Heterochronic parabiosis exploiting young mice in which macrophages can be depleted and fractionated bone marrow transplantation experiments show that young macrophages rejuvenate fracture repair, and old macrophage cells slow healing in young mice. Proteomic analysis of the secretomes identify differential proteins secreted between old and young macrophages, such as low-density lipoprotein receptor-related protein 1 (Lrp1). Lrp1 is produced by young cells, and depleting Lrp1 abrogates the ability to rejuvenate fracture repair, while treating old mice with recombinant Lrp1 improves fracture healing. Macrophages and proteins they secrete orchestrate the fracture repair process, and young cells produce proteins that rejuvenate fracture repair in mice.
  • Thumbnail Image
    ItemOpen Access
    Microgravity induces proteomics changes involved in endoplasmic reticulum stress and mitochondrial protection.
    (Scientific reports, 2016-09-27) Feger, Bryan J; Thompson, J Will; Dubois, Laura G; Kommaddi, Reddy P; Foster, Matthew W; Mishra, Rajashree; Shenoy, Sudha K; Shibata, Yoichiro; Kidane, Yared H; Moseley, M Arthur; Carnell, Lisa S; Bowles, Dawn E
    On Earth, biological systems have evolved in response to environmental stressors, interactions dictated by physical forces that include gravity. The absence of gravity is an extreme stressor and the impact of its absence on biological systems is ill-defined. Astronauts who have spent extended time under conditions of minimal gravity (microgravity) experience an array of biological alterations, including perturbations in cardiovascular function. We hypothesized that physiological perturbations in cardiac function in microgravity may be a consequence of alterations in molecular and organellar dynamics within the cellular milieu of cardiomyocytes. We used a combination of mass spectrometry-based approaches to compare the relative abundance and turnover rates of 848 and 196 proteins, respectively, in rat neonatal cardiomyocytes exposed to simulated microgravity or normal gravity. Gene functional enrichment analysis of these data suggested that the protein content and function of the mitochondria, ribosomes, and endoplasmic reticulum were differentially modulated in microgravity. We confirmed experimentally that in microgravity protein synthesis was decreased while apoptosis, cell viability, and protein degradation were largely unaffected. These data support our conclusion that in microgravity cardiomyocytes attempt to maintain mitochondrial homeostasis at the expense of protein synthesis. The overall response to this stress may culminate in cardiac muscle atrophy.
  • Thumbnail Image
    ItemOpen Access
    The utility of nuclear gapCp in resolving polyploid fern origins
    (Systematic Botany, 2008-10-01) Schuettpelz, E; Grusz, AL; Windham, MD; Pryer, KM
    Although polyploidy is rampant in ferns and plays a major role in shaping their diversity, the evolutionary history of many polyploid species remains poorly understood. Nuclear DNA sequences can provide valuable information for identifying polyploid origins; however, remarkably few nuclear markers have been developed specifically for ferns, and previously published primer sets do not work well in many fern lineages. In this study, we present new primer sequences for the amplification of a portion of the nuclear gapCp gene (encoding a glyceraldehyde-3-phosphate dehydrogenase). Through a broad survey across ferns, we demonstrate that these primers are nearly universal for this clade. With a case study in cheilanthoids, we show that this rapidly evolving marker is a powerful tool for discriminating between autopolyploids and allopolyploids. Our results indicate that gapCp holds considerable potential for addressing species-level questions across the fern tree of life. © Copyright 2008 by the American Society of Plant Taxonomists.