{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n CNGB3 encodes the beta‐subunit of cone cyclic nucleotide–gated (CNG) channels, which are essential components of the phototransduction cascade in cone photoreceptors. In concert with the alpha‐subunit (CNGA3), the CNGB3 gene product assembles into a heterotetrameric channel complex that is pivotal for regulating ion flow and setting the channel’s sensitivity to cyclic nucleotides—processes that are fundamental for color vision and high–visual acuity ["}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "3"}]}, {"type": "t", "text": "]."}]}, {"type": "t", "text": "\n \n "}, {"type": "p", "children": [{"type": "t", "text": "\n Detailed functional analyses have shown that CNGB3 not only serves as a modulatory scaffold that fine–tunes channel gating and ligand affinity but also influences the overall expression levels and stability of the channel complex. Mutations in CNGB3—many of which lead to truncated or functionally altered proteins—disrupt these critical processes, resulting in impaired phototransduction and cone degeneration. Such mutations are responsible for the majority of achromatopsia cases and have been linked to a spectrum of cone dysfunction, ranging from complete achromatopsia to progressive cone dystrophy ["}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "4", "end_ref": "9"}]}, {"type": "t", "text": "].\n "}]}, {"type": "t", "text": "\n \n "}, {"type": "p", "children": [{"type": "t", "text": "\n Furthermore, preclinical studies using animal models of CNGB3-associated achromatopsia have demonstrated that subretinal delivery of a functional CNGB3 gene via adeno-associated virus gene therapy can effectively restore cone function. This therapeutic approach not only confirms the central role of CNGB3 in maintaining proper cone physiology but also underscores its potential as a target for future treatments of congenital cone disorders ["}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}, {"type": "fg_f", "ref": "10"}]}, {"type": "t", "text": "]. \n "}]}, {"type": "t", "text": "\n \n "}, {"type": "p", "children": [{"type": "t", "text": "\n In summary, CNGB3 is critical for the proper assembly, modulation, and function of cone CNG channels. Disruption of its normal activity by genetic mutations leads to significant cone pathologies, while reinstating its function via gene augmentation offers promising therapeutic avenues for achromatopsia and other cone-specific retinal diseases.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "András M Komáromy, John J Alexander, Jessica S Rowlan, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Gene therapy rescues cone function in congenital achromatopsia."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Hum Mol Genet (2010)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1093/hmg/ddq136"}], "href": "https://doi.org/10.1093/hmg/ddq136"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "20378608"}], "href": "https://pubmed.ncbi.nlm.nih.gov/20378608"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Changhong Peng, Elizabeth D Rich, Michael D Varnum "}, {"type": "b", "children": [{"type": "t", "text": "Subunit configuration of heteromeric cone cyclic nucleotide-gated channels."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Neuron (2004)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/s0896-6273(04)00225-9"}], "href": "https://doi.org/10.1016/s0896-6273(04"}, {"type": "t", "text": "00225-9) PMID: "}, {"type": "a", "children": [{"type": "t", "text": "15134637"}], "href": "https://pubmed.ncbi.nlm.nih.gov/15134637"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Xi-Qin Ding, Cynthia S Harry, Yumiko Umino, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Impaired cone function and cone degeneration resulting from CNGB3 deficiency: down-regulation of CNGA3 biosynthesis as a potential mechanism."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Hum Mol Genet (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1093/hmg/ddp440"}], "href": "https://doi.org/10.1093/hmg/ddp440"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19767295"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19767295"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Susanne Kohl, Balazs Varsanyi, Gesine Abadin Antunes, et al. "}, {"type": "b", "children": [{"type": "t", "text": "CNGB3 mutations account for 50% of all cases with autosomal recessive achromatopsia."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Eur J Hum Genet (2005)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/sj.ejhg.5201269"}], "href": "https://doi.org/10.1038/sj.ejhg.5201269"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "15657609"}], "href": "https://pubmed.ncbi.nlm.nih.gov/15657609"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Changhong Peng, Elizabeth D Rich, Michael D Varnum "}, {"type": "b", "children": [{"type": "t", "text": "Achromatopsia-associated mutation in the human cone photoreceptor cyclic nucleotide-gated channel CNGB3 subunit alters the ligand sensitivity and pore properties of heteromeric channels."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M305102200"}], "href": "https://doi.org/10.1074/jbc.M305102200"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12815043"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12815043"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Changhong Peng, Elizabeth D Rich, Christopher A Thor, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Functionally important calmodulin-binding sites in both NH2- and COOH-terminal regions of the cone photoreceptor cyclic nucleotide-gated channel CNGB3 subunit."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2003)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M301699200"}], "href": "https://doi.org/10.1074/jbc.M301699200"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "12730238"}], "href": "https://pubmed.ncbi.nlm.nih.gov/12730238"}]}, {"type": "r", "ref": 7, "children": [{"type": "t", "text": "Hongwei Ma, Michael R Butler, Arjun Thapa, et al. "}, {"type": "b", "children": [{"type": "t", "text": "cGMP/Protein Kinase G Signaling Suppresses Inositol 1,4,5-Trisphosphate Receptor Phosphorylation and Promotes Endoplasmic Reticulum Stress in Photoreceptors of Cyclic Nucleotide-gated Channel-deficient Mice."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biol Chem (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1074/jbc.M115.641159"}], "href": "https://doi.org/10.1074/jbc.M115.641159"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "26124274"}], "href": "https://pubmed.ncbi.nlm.nih.gov/26124274"}]}, {"type": "r", "ref": 8, "children": [{"type": "t", "text": "Scott R Bright, Travis E Brown, Michael D Varnum "}, {"type": "b", "children": [{"type": "t", "text": "Disease-associated mutations in CNGB3 produce gain of function alterations in cone cyclic nucleotide-gated channels."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Vis (2005)"}]}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16379026"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16379026"}]}, {"type": "r", "ref": 9, "children": [{"type": "t", "text": "Balázs Varsányi, Bernd Wissinger, Susanne Kohl, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Clinical and genetic features of Hungarian achromatopsia patients."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Vis (2005)"}]}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16319819"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16319819"}]}, {"type": "r", "ref": 10, "children": [{"type": "t", "text": "Guo-Jie Ye, András M Komáromy, Caroline Zeiss, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Safety and Efficacy of AAV5 Vectors Expressing Human or Canine CNGB3 in CNGB3-Mutant Dogs."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Hum Gene Ther Clin Dev (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1089/humc.2017.125"}], "href": "https://doi.org/10.1089/humc.2017.125"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "29020838"}], "href": "https://pubmed.ncbi.nlm.nih.gov/29020838"}]}]}]}