{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nRecent studies have revealed a unique glycosylation pathway in mucus‐secreting cells involving a novel α1,4‑N‑acetylglucosaminyltransferase (α4GnT). This enzyme, identified from human gastric and pancreatic tissues, catalyzes the formation of class III mucin by transferring α1,4‑linked N‑acetylglucosamine residues to core 2 branched O‑glycans. This modification underlies the distinct Con A reactivity observed in these cells and defines a specialized mucin biosynthetic program important for normal gastric physiology."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nFunctional investigations in animal models and clinical specimens have underscored a protective role for these glycan-capped mucins. Mice lacking α4GnT fail to express α1,4‑linked N‑acetylglucosamine on gastric mucin and develop gastric adenocarcinoma through an inflammation-associated hyperplasia-dysplasia-carcinoma sequence, even in the absence of Helicobacter pylori infection. In humans, diminished expression of these signature glycans correlates with gastric adenoma and carcinoma, and additional studies further demonstrate that the terminal α1,4‑GlcNAc on mucin strongly inhibits H. pylori growth."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn a related line of inquiry into host defense mechanisms against viral pathogens, analyses of the tripartite motif (TRIM) family have revealed surprising functional interchangeability among its members. Experiments replacing the RING, B-box 2, and coiled-coil domains of rhesus TRIM5α with those from the paralogous TRIM6 and TRIM34 proteins showed that these heterologous domains can reconstitute HIV‑1 restriction. The chimeric proteins not only form the requisite trimers but also correctly interact with assembled HIV‑1 capsid complexes, highlighting a conserved structural and functional role within this TRIM subgroup in mediating retroviral defense."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": ""}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "J Nakayama, J C Yeh, A K Misra, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Expression cloning of a human alpha1, 4-N-acetylglucosaminyltransferase that forms GlcNAcalpha1-->4Galbeta-->R, a glycan specifically expressed in the gastric gland mucous cell-type mucin."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Proc Natl Acad Sci U S A (1999)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1073/pnas.96.16.8991"}], "href": "https://doi.org/10.1073/pnas.96.16.8991"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "10430883"}], "href": "https://pubmed.ncbi.nlm.nih.gov/10430883"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Fumitoshi Karasawa, Akira Shiota, Yukinobu Goso, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Essential role of gastric gland mucin in preventing gastric cancer in mice."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Clin Invest (2012)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1172/JCI59087"}], "href": "https://doi.org/10.1172/JCI59087"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "22307328"}], "href": "https://pubmed.ncbi.nlm.nih.gov/22307328"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Zongli Zheng, Yanbin Jia, Lifang Hou, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Genetic variation in a4GnT in relation to Helicobacter pylori serology and gastric cancer risk."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Helicobacter (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1111/j.1523-5378.2009.00708.x"}], "href": "https://doi.org/10.1111/j.1523-5378.2009.00708.x"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19751437"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19751437"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Xing Li, Yuan Li, Matthew Stremlau, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Functional replacement of the RING, B-box 2, and coiled-coil domains of tripartite motif 5alpha (TRIM5alpha) by heterologous TRIM domains."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Virol (2006)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1128/JVI.00283-06"}], "href": "https://doi.org/10.1128/JVI.00283-06"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16775307"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16775307"}]}]}]}