{"doi":"10.1167/iovs.61.4.26","title":"Diminished Cone Sensitivity in <i>cpfl3</i> Mice Is Caused by Defective Transducin Signaling","abstract":"Purpose: Cone photoreceptor function loss 3 (Gnat2cpfl3/cpfl3 or cpfl3) is a mouse model commonly used as a functional cones null from a naturally occurring mutation in the α-subunit of cone transducin (Gnat2). We nevertheless detected robust cone-mediated light responses from cpfl3 animals, which we now explore. Methods: Recordings were made from whole retina and from identified cones with whole-cell patch clamp in retinal slices. Relative levels of GNAT2 protein and numbers of cones in isolated retinas were compared between cpfl3, rod transducin knockout (Gnat1-/-), cpfl3/Gnat1-/- double mutants, and control C57Bl/6J age-matched mice at 4, 9, and 14 weeks of age. Results: Cones from cpfl3 and cpfl3/Gnat1-/- mice 2 to 3 months of age displayed normal dark currents but greatly reduced sensitivity and amplification constants. Responses decayed more slowly than in control (C57Bl/6J) mice, indicating an altered mechanism of inactivation. At dim light intensities rod responses could be recorded from cpfl3 cones, indicating intact rod/cone gap junctions. The cpfl3 and cpfl3/Gnat1-/- mice express two-fold less GNAT2 protein compared with C57 at 4 weeks, and a four-fold decrease by 14 weeks. This is accompanied by a small decrease in the number of cones. Conclusions: Cplf3 cones can respond to light with currents of normal amplitude and cannot be assumed to be a Gnat2 null. The decreased sensitivity and amplification rate of cones is not explained by a reduction in GNAT2 protein level, but instead by abnormal interactions of the mutant transducin with rhodopsin and the effector molecule, cGMP phosphodiesterase.","journal":"Investigative Ophthalmology & Visual Science","year":2020,"id":107957,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":5,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9087,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":267847,"name":"Norianne T. Ingram","orcid":"0000-0002-5852-0944","position":1,"is_corresponding":false},{"id":442394,"name":"Rikard Frederiksen","orcid":"0000-0001-7999-8480","position":2,"is_corresponding":false},{"id":267849,"name":"Alapakkam P. Sampath","orcid":"0000-0002-0785-9577","position":3,"is_corresponding":false},{"id":382925,"name":"Jeannie Chen","orcid":"0000-0002-7904-9629","position":4,"is_corresponding":false},{"id":267848,"name":"Gordon Fain","orcid":"0000-0002-9813-0342","position":5,"is_corresponding":false},{"id":517879,"name":"Natalie S. Chen","orcid":"0000-0001-9706-6679","position":0,"is_corresponding":true}],"reference_count":39,"raw_metadata":null,"created_at":"2026-07-18T23:12:39.385256Z","pmid":"32315379","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}