Xylosyltransferase 1 is an enzyme that in humans is encoded by the XYLT1gene.
Xylosyltransferase (XT; EC 126.96.36.199) catalyzes the transfer of UDP-xylose to serine residues within XT recognition sequences of target proteins. Addition of this xylose to the core protein is required for the biosynthesis of the glycosaminoglycan chains characteristic of proteoglycans.[supplied by OMIM]
Clinical relevance: Neurons use the presence of extracellular matrix molecules as clues whether to promote or suppress extension of axons. Chondroitin sulfate proteoglycans suppress the extension of axons over the glial scar, a barrier which develops after lesioning the spinal cord. Proteoglycans consist of one relatively small protein core and attached large glycosaminoglycan side chains. To block the very formation of these side chains xylosyltransferase (XYLT1) which attaches xylose to a serine of the protein core as initiation for glycosaminoglycan chain extension, was targeted by a class of designed DNA molecules. These molecules are called DNA-enzymes which were designed to specifically cleave XYLT1 mRNA within cells. DNA-enzymes are readily taken up by mammalian cells, but are more stable and require much lower concentrations then e.g. siRNA. And indeed, XTYL1 DNA-enzyme in co-cultures of neurons with neurocan secreting cells displayed a marked increase of axon outgrowth. Rats with defined spinal cord lesions, i.a. the clinically relevant contusion injury, treated with XTYL1 DNA-enzyme administered by micro-infusion pumps or systemically achieved improvements in the horizontal ladder task, enhanced axonal plasticity, growth of the corticospinal tract, no effect on neuropathic pain when using mechanical and thermal allodynia tests and no toxicological or pathological side effects compared to control animals.
^Gotting C, Kuhn J, Zahn R, Brinkmann T, Kleesiek K (Jan 2001). "Molecular cloning and expression of human UDP-d-Xylose:proteoglycan core protein beta-d-xylosyltransferase and its first isoform XT-II". J Mol Biol. 304 (4): 517–28. doi:10.1006/jmbi.2000.4261. PMID11099377.
Götting C, Sollberg S, Kuhn J, et al. (1999). "Serum xylosyltransferase: a new biochemical marker of the sclerotic process in systemic sclerosis". J. Invest. Dermatol. 112 (6): 919–24. doi:10.1046/j.1523-1747.1999.00590.x. PMID10383739.
Kuhn J, Götting C, Schnölzer M, et al. (2001). "First isolation of human UDP-D-xylose: proteoglycan core protein beta-D-xylosyltransferase secreted from cultured JAR choriocarcinoma cells". J. Biol. Chem. 276 (7): 4940–7. doi:10.1074/jbc.M005111200. PMID11087729.
Götting C, Müller S, Schöttler M, et al. (2004). "Analysis of the DXD motifs in human xylosyltransferase I required for enzyme activity". J. Biol. Chem. 279 (41): 42566–73. doi:10.1074/jbc.M401340200. PMID15294915.
Götting C, Hendig D, Adam A, et al. (2006). "Elevated xylosyltransferase I activities in pseudoxanthoma elasticum (PXE) patients as a marker of stimulated proteoglycan biosynthesis". J. Mol. Med. 83 (12): 984–92. doi:10.1007/s00109-005-0693-x. PMID16133423.
Schön S, Prante C, Müller S, et al. (2005). "Impact of polymorphisms in the genes encoding xylosyltransferase I and a homologue in type 1 diabetic patients with and without nephropathy". Kidney Int. 68 (4): 1483–90. doi:10.1111/j.1523-1755.2005.00561.x. PMID16164625.
Schön S, Prante C, Bahr C, et al. (2006). "Cloning and recombinant expression of active full-length xylosyltransferase I (XT-I) and characterization of subcellular localization of XT-I and XT-II". J. Biol. Chem. 281 (20): 14224–31. doi:10.1074/jbc.M510690200. PMID16569644.
Prante C, Bieback K, Funke C, et al. (2006). "The formation of extracellular matrix during chondrogenic differentiation of mesenchymal stem cells correlates with increased levels of xylosyltransferase I.". Stem Cells. 24 (10): 2252–61. doi:10.1634/stemcells.2005-0508. PMID16778156.
Schön S, Prante C, Bahr C, et al. (2007). "The xylosyltransferase I gene polymorphism c.343G>T (p.A125S) is a risk factor for diabetic nephropathy in type 1 diabetes". Diabetes Care. 29 (10): 2295–9. doi:10.2337/dc06-0344. PMID17003309.
Cuellar K, Chuong H, Hubbell SM, Hinsdale ME (2007). "Biosynthesis of chondroitin and heparan sulfate in chinese hamster ovary cells depends on xylosyltransferase II". J. Biol. Chem. 282 (8): 5195–200. doi:10.1074/jbc.M611048200. PMID17189266.
Prante C, Milting H, Kassner A, et al. (2007). "Transforming growth factor beta1-regulated xylosyltransferase I activity in human cardiac fibroblasts and its impact for myocardial remodeling". J. Biol. Chem. 282 (36): 26441–9. doi:10.1074/jbc.M702299200. PMID17635914.
Grimpe B, Pressman Y, Lupa MD, Horn KP, Bunge MB, Silver J (2005). "The role of proteoglycans in Schwann cell/astrocyte interactions and in regeneration failure at PNS/CNS interfaces". Molecular and Cellular Neuroscience. 28: 18–29. doi:10.1016/j.mcn.2004.06.010. PMID15607938.
Hurtado A, Podini H, Oudega M, Grimpe B (2008). "Deoxyribozyme-mediated knock down of xylosyltransferase-1 mRNA promotes axon growth in the adult rat spinal cord". Brain. 131: 2596–605. doi:10.1093/brain/awn206. PMID18765417.
Koenig B, Pape D, Chao O, Bauer J, Grimpe B (2016). "Long term study of deoxyribozyme administration to XT-1 mRNA promotes cortiospinal tract regeneration and improves behavioral outcome after spinal cord injury". Experimental Neurology. 276: 51–58. doi:10.1016/j.expneurol.2015.09.015. PMID26428904.
Oudega M, Chao OY, Avison DL, Bronson RT, Buchser WJ, Hurtado A, Grimpe B (2012). "Systemic administration of a deoxyribozyme to xylosyltransferase-1 mRNA promotes recovery after a spinal cord contusion injury,". Experimental Neurology. 237: 170–179. doi:10.1016/j.expneurol.2012.06.006. PMID22721770.