{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T18:32:55Z","timestamp":1790706775180,"version":"4.1.0"},"reference-count":61,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,3,19]],"date-time":"2025-03-19T00:00:00Z","timestamp":1742342400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:sec><jats:title>Introduction<\/jats:title><jats:p>Genetic manipulation of murine retinal tissue through ocular administration of adeno-associated viruses (AAVs) has become a standard technique to investigate a multitude of mechanisms underlying retinal physiology. Resultantly, developments of recombinant viral vectors with improved transduction efficiency and further methodological improvements have mostly focused on murine tissue, whereas AAVs successfully targeting avian retinae have remained scarce.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methodology<\/jats:title><jats:p>Using a custom-designed injection setup, we identified a viral serotype with the capability to successfully induce widespread transduction of the bird retina.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Intravitreal administration of an AAV type 2\/9 encoding for enhanced green fluorescent protein (EGFP) in night-migratory European robins (<jats:italic>Erithacus rubecula<\/jats:italic>) resulted in transduction coverages of up to 60% within retinal tissue. Subsequent immunohistochemical analyses revealed that the AAV2\/9-EGFP serotype almost exclusively targeted photoreceptors: rods, various single cones (UV, blue, green, and red cones), and both (accessory and principal) members of double cones.<\/jats:p><\/jats:sec><jats:sec><jats:title>Discussion<\/jats:title><jats:p>The consistently high and photoreceptor-specific transduction efficiency makes the AAV2\/9 serotype a powerful tool for carrying out genetic manipulations in avian retinal photoreceptors, thus opening a wealth of opportunities to investigate physiological aspects underlying retinal processing in birds, such as physiological recordings and\/or post-transductional behavioural readouts for future vision-related research.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fphys.2025.1549585","type":"journal-article","created":{"date-parts":[[2025,3,19]],"date-time":"2025-03-19T07:12:19Z","timestamp":1742368339000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["AAV-mediated transduction of songbird retina"],"prefix":"10.3389","volume":"16","author":[{"given":"Pranav Kumar","family":"Seth","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dominik","family":"Heyers","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Baladev","family":"Satish","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ezequiel","family":"Mendoza","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katrin","family":"Haase","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa","family":"Borowsky","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Isabelle","family":"Musielak","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karl-Wilhelm","family":"Koch","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Regina","family":"Feederle","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Constance","family":"Scharff","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karin","family":"Dedek","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Henrik","family":"Mouritsen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,3,19]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"43244","DOI":"10.1038\/srep43244","article-title":"A reliable and flexible gene manipulation strategy in posthatch zebra finch brain","volume":"7","author":"Ahmadiantehrani","year":"2017","journal-title":"Sci. Rep."},{"key":"B2","doi-asserted-by":"publisher","first-page":"306","DOI":"10.1038\/77068","article-title":"Restoration of photoreceptor ultrastructure and function in retinal degeneration slow mice by gene therapy","volume":"25","author":"Ali","year":"2000","journal-title":"Nat. Genet."},{"key":"B3","doi-asserted-by":"publisher","first-page":"11372","DOI":"10.1128\/jvi.01327-07","article-title":"Novel adeno-associated virus serotypes efficiently transduce murine photoreceptors","volume":"81","author":"Allocca","year":"2007","journal-title":"J. Virol."},{"key":"B4","doi-asserted-by":"publisher","first-page":"754","DOI":"10.1126\/science.149.3685.754","article-title":"Adenovirus-associated defective virus particles","volume":"149","author":"Atchison","year":"1965","journal-title":"Science"},{"key":"B5","doi-asserted-by":"publisher","first-page":"708","DOI":"10.3390\/life12050708","article-title":"Treatment of inherited retinal dystrophies with somatic cell therapy medicinal product: a review","volume":"12","author":"Bacci","year":"2022","journal-title":"Life"},{"key":"B6","doi-asserted-by":"publisher","first-page":"561","DOI":"10.1002\/cne.25443","article-title":"Immunohistochemical characterization of bipolar cells in four distantly related avian species","volume":"531","author":"Balaji","year":"2023","journal-title":"J. Comp. Neurology"},{"key":"B7","doi-asserted-by":"publisher","first-page":"86","DOI":"10.2174\/1566523214666140302193709","article-title":"Basic biology of adeno-associated virus (AAV) vectors used in gene therapy","volume":"14","author":"Balakrishnan","year":"2014","journal-title":"Curr. Gene. Ther."},{"key":"B8","doi-asserted-by":"publisher","first-page":"486","DOI":"10.1002\/jgm.1327","article-title":"Subretinal delivery of adeno\u2010associated virus serotype 2 results in minimal immune responses that allow repeat vector administration in immunocompetent mice","volume":"11","author":"Barker","year":"2009","journal-title":"J. Gene. Med."},{"key":"B9","first-page":"2535","article-title":"Adenovirus vector-mediated in vivo gene transfer into adult murine retina","volume":"35","author":"Bennett","year":"1994","journal-title":"Investigative Ophthalmol. and Vis. Sci."},{"key":"B10","doi-asserted-by":"publisher","first-page":"849","DOI":"10.1038\/gt.2008.66","article-title":"AAV-mediated gene therapy for retinal disorders: from mouse to man","volume":"15","author":"Buch","year":"2008","journal-title":"Gene. Ther."},{"key":"B11","doi-asserted-by":"publisher","first-page":"2345","DOI":"10.1016\/j.visres.2008.08.001","article-title":"The scaling of eye size in adult birds: relationship to brain, head and body sizes","volume":"48","author":"Burton","year":"2008","journal-title":"Vis. Res."},{"key":"B12","doi-asserted-by":"publisher","first-page":"e44257","DOI":"10.1371\/journal.pone.0044257","article-title":"A chick model of retinal detachment: cone rich and novel","volume":"7","author":"Cebulla","year":"2012","journal-title":"PLoS. One."},{"key":"B13","doi-asserted-by":"publisher","first-page":"20210877","DOI":"10.1098\/rsif.2021.0877","article-title":"Double cones in the avian retina form an oriented mosaic which might facilitate magnetoreception and\/or polarized light sensing","volume":"19","author":"Chetverikova","year":"2022","journal-title":"J. R. Soc. Interface"},{"key":"B14","doi-asserted-by":"publisher","first-page":"2096","DOI":"10.1038\/mt.2009.181","article-title":"Inner limiting membrane barriers to AAV-mediated retinal transduction from the vitreous","volume":"17","author":"Dalkara","year":"2009","journal-title":"Mol. Ther."},{"key":"B15","doi-asserted-by":"publisher","first-page":"652","DOI":"10.1016\/j.exer.2010.08.011","article-title":"Transduction of the inner mouse retina using AAVrh8 and AAVrh10 via intravitreal injection","volume":"91","author":"Giove","year":"2010","journal-title":"Exp. Eye Res."},{"key":"B16","doi-asserted-by":"publisher","first-page":"2043","DOI":"10.3390\/cells11132043","article-title":"Direct interaction of avian cryptochrome 4 with a cone specific G-protein","volume":"11","author":"G\u00f6rtemaker","year":"2022","journal-title":"Cells"},{"key":"B17","doi-asserted-by":"publisher","DOI":"10.3389\/fncel.2025.1558605","article-title":"Morphology and connectivity of retinal horizontal cells in two avian species","volume":"19","author":"G\u00fcnther","year":"2025","journal-title":"Front. Cell. Neurosci."},{"key":"B18","doi-asserted-by":"publisher","first-page":"5015","DOI":"10.1523\/JNEUROSCI.2495-20.2021","article-title":"Double cones and the diverse connectivity of photoreceptors and bipolar cells in an avian retina","volume":"41","author":"G\u00fcnther","year":"2021","journal-title":"J. Neurosci."},{"key":"B19","doi-asserted-by":"publisher","first-page":"211","DOI":"10.1016\/j.cub.2017.12.003","article-title":"Double-cone localization and seasonal expression pattern suggest a role in magnetoreception for European robin cryptochrome 4","volume":"28","author":"G\u00fcnther","year":"2018","journal-title":"Curr. Biol."},{"key":"B20","doi-asserted-by":"publisher","first-page":"992","DOI":"10.1038\/s42003-024-06697-2","article-title":"Species\u2013specific circuitry of double cone photoreceptors in two avian retinas","volume":"7","author":"G\u00fcnther","year":"2024","journal-title":"Commun. Biol."},{"key":"B21","volume-title":"Anatomy of the avian thalamofugal pathway","author":"G\u00fcnt\u00fcrk\u00fcn","year":"1993"},{"key":"B22","doi-asserted-by":"publisher","first-page":"2","DOI":"10.1186\/1471-213X-6-2","article-title":"RCAS-RNAi: a loss-of-function method for the developing chick retina","volume":"6","author":"Harpavat","year":"2006","journal-title":"Bmc. Dev. Biol."},{"key":"B23","doi-asserted-by":"publisher","first-page":"3171","DOI":"10.1002\/cne.25154","article-title":"Expression of cell markers and transcription factors in the avian retina compared with that in the marmoset retina","volume":"529","author":"Haverkamp","year":"2021","journal-title":"J. Comp. Neurol."},{"key":"B24","doi-asserted-by":"publisher","first-page":"299","DOI":"10.1146\/annurev-biophys-032116-094545","article-title":"The radical-pair mechanism of magnetoreception","volume":"45","author":"Hore","year":"2016","journal-title":"Annu. Rev. Biophys."},{"key":"B25","doi-asserted-by":"publisher","first-page":"3610","DOI":"10.1167\/iovs.16-19300","article-title":"Intravitreal injection of proinsulin-loaded microspheres delays photoreceptor cell death and vision loss in the rd10 mouse model of retinitis pigmentosa","volume":"57","author":"Isiegas","year":"2016","journal-title":"Invest. Ophthalmol. Vis. Sci."},{"key":"B26","doi-asserted-by":"publisher","first-page":"8936","DOI":"10.1523\/JNEUROSCI.18-21-08936.1998","article-title":"The major cell populations of the mouse retina","volume":"18","author":"Jeon","year":"1998","journal-title":"J. Neurosci."},{"key":"B27","doi-asserted-by":"publisher","first-page":"117","DOI":"10.1016\/0014-5793(94)00512-5","article-title":"Adenovirus\u2010mediated gene transfer to murine retinal cells in vitro and in vivo","volume":"347","author":"Jomary","year":"1994","journal-title":"Febs. Lett."},{"key":"B28","doi-asserted-by":"publisher","first-page":"69","DOI":"10.1053\/j.jepm.2007.03.012","article-title":"Avian vision: a review of form and function with special consideration to birds of prey","volume":"16","author":"Jones","year":"2007","journal-title":"J. Exot. Pet. Med."},{"key":"B29","doi-asserted-by":"publisher","first-page":"384","DOI":"10.1089\/jop.2019.0126","article-title":"Suprachoroidal delivery of viral and nonviral gene therapy for retinal diseases","volume":"36","author":"Kansara","year":"2020","journal-title":"J. Ocul. Pharmacol. Ther."},{"key":"B30","doi-asserted-by":"publisher","first-page":"2712","DOI":"10.1002\/bit.26031","article-title":"Insight into the mechanisms of enhanced retinal transduction by the engineered AAV2 capsid variant -7m8","volume":"113","author":"Khabou","year":"2016","journal-title":"Biotechnol. Bioeng."},{"key":"B31","doi-asserted-by":"publisher","first-page":"55","DOI":"10.1016\/j.omtm.2018.11.008","article-title":"Adeno-associated viral vector 2 and 9 transduction is enhanced in streptozotocin-induced diabetic mouse retina","volume":"13","author":"Lee","year":"2018","journal-title":"Mol. Ther. Methods Clin. Dev."},{"key":"B32","first-page":"2543","article-title":"In vivo transfer of a reporter gene to the retina mediated by an adenoviral vector","volume":"35","author":"Li","year":"1994","journal-title":"Invest. Ophthalmol. Vis. Sci."},{"key":"B33","doi-asserted-by":"publisher","first-page":"50","DOI":"10.1038\/s41586-018-0176-1","article-title":"Long-distance navigation and magnetoreception in migratory animals","volume":"558","author":"Mouritsen","year":"2018","journal-title":"Nature"},{"key":"B34","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/B978-0-12-819770-7.00040-2","article-title":"Magnetoreception in birds and its use for long-distance migration","volume-title":"Sturkie's avian physiology","author":"Mouritsen","year":"2022"},{"key":"B35","doi-asserted-by":"publisher","first-page":"343","DOI":"10.1007\/978-1-62703-080-9_24","article-title":"Optimized technique for subretinal injections in mice","volume":"935","author":"M\u00fchlfriedel","year":"2013","journal-title":"Methods. Mol. Biol."},{"key":"B36","doi-asserted-by":"publisher","first-page":"503","DOI":"10.1038\/s41434-022-00380-z","article-title":"Improving adeno-associated viral (AAV) vector-mediated transgene expression in retinal ganglion cells: comparison of five promoters","volume":"30","author":"Nieuwenhuis","year":"2023","journal-title":"Gene Ther."},{"key":"B37","doi-asserted-by":"publisher","first-page":"100023","DOI":"10.1016\/j.avrs.2022.100023","article-title":"Visual cognition of birds and its underlying neural mechanism: a review","volume":"13","author":"Niu","year":"2022","journal-title":"Avian. Res."},{"key":"B38","doi-asserted-by":"publisher","first-page":"34","DOI":"10.1007\/s11095-018-2564-5","article-title":"Adeno-associated viral gene therapy for inherited retinal disease","volume":"36","author":"Ong","year":"2019","journal-title":"Pharm. Res."},{"key":"B39","doi-asserted-by":"publisher","first-page":"53030","DOI":"10.3791\/53030","article-title":"Limbal approach-subretinal injection of viral vectors for gene therapy in mice retinal pigment epithelium","volume":"102","author":"Park","year":"2015","journal-title":"J. Vis. Exp."},{"key":"B40","doi-asserted-by":"publisher","first-page":"464","DOI":"10.1089\/hum.2017.020","article-title":"Rod outer segment development influences AAV-mediated photoreceptor transduction after subretinal injection","volume":"28","author":"Petit","year":"2017","journal-title":"Hum. Gene. Ther."},{"key":"B41","doi-asserted-by":"publisher","first-page":"6429","DOI":"10.1167\/iovs.17-22281","article-title":"Improvement of photoreceptor targeting via intravitreal delivery in mouse and human retina using combinatory rAAV2 capsid mutant vectors","volume":"58","author":"Reid","year":"2017","journal-title":"Invest. Ophthalmol. Vis. Sci."},{"key":"B42","doi-asserted-by":"publisher","first-page":"670","DOI":"10.3389\/fimmu.2020.00670","article-title":"Human immune responses to adeno-associated virus (AAV) vectors","volume":"11","author":"Ronzitti","year":"2020","journal-title":"Front. Immunol."},{"key":"B43","doi-asserted-by":"publisher","first-page":"3056","DOI":"10.3390\/cells11193056","article-title":"Magnetoreceptory function of European robin retina: electrophysiological and morphological non-homogeneity","volume":"11","author":"Rotov","year":"2022","journal-title":"Cells"},{"key":"B44","doi-asserted-by":"publisher","first-page":"676","DOI":"10.1038\/nmeth.2019","article-title":"Fiji: an open-source platform for biological-image analysis","volume":"9","author":"Schindelin","year":"2012","journal-title":"Nat. Methods."},{"key":"B45","doi-asserted-by":"publisher","first-page":"523","DOI":"10.1038\/sj.gt.3301929","article-title":"Intraocular gene delivery of ciliary neurotrophic factor results in significant loss of retinal function in normal mice and in the Prph2Rd2\/Rd2 model of retinal degeneration","volume":"10","author":"Schlichtenbrede","year":"2003","journal-title":"Gene. Ther."},{"key":"B46","doi-asserted-by":"publisher","first-page":"16443","DOI":"10.1073\/pnas.0508437102","article-title":"Generation of tissue-specific transgenic birds with lentiviral vectors","volume":"102","author":"Scott","year":"2005","journal-title":"Proc. Natl. Acad. Sci. USA."},{"key":"B47","doi-asserted-by":"publisher","first-page":"106","DOI":"10.1016\/j.semcdb.2020.03.011","article-title":"The retinal basis of vision in chicken","volume":"106","author":"Seifert","year":"2020","journal-title":"Semin. Cell Dev. Biol."},{"key":"B48","doi-asserted-by":"publisher","first-page":"179","DOI":"10.1007\/978-1-61779-370-7_8","article-title":"Adeno-associated virus mediated gene therapy for retinal degenerative diseases","volume":"807","author":"Stieger","year":"2011","journal-title":"Methods. Mol. Biol."},{"key":"B49","doi-asserted-by":"publisher","first-page":"22","DOI":"10.1186\/1749-8104-7-22","article-title":"Rediscovering the chick embryo as a model to study retinal development","volume":"7","author":"Vergara","year":"2012","journal-title":"Neural. Dev."},{"key":"B50","doi-asserted-by":"publisher","first-page":"e20553","DOI":"10.1371\/journal.pone.0020553","article-title":"Bicistronic lentiviruses containing a viral 2A cleavage sequence reliably co-express two proteins and restore vision to an animal model of LCA1","volume":"6","author":"Verrier","year":"2011","journal-title":"PloS. One."},{"key":"B51","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1167\/tvst.8.4.1","article-title":"Avian adeno-associated viral transduction of the postembryonic chicken retina","volume":"8","author":"Waldner","year":"2019","journal-title":"Transl. Vis. Sci. Technol."},{"key":"B52","first-page":"342","article-title":"The bird's eye view","volume":"78","author":"Waldvogel","year":"1990","journal-title":"Am. Sci."},{"key":"B53","doi-asserted-by":"publisher","first-page":"1397","DOI":"10.1038\/s41477-021-01002-z","article-title":"A photoregulatory mechanism of the circadian clock in Arabidopsis","volume":"7","author":"Wang","year":"2021","journal-title":"Nat. Plants"},{"key":"B54","doi-asserted-by":"publisher","first-page":"e54146","DOI":"10.1371\/journal.pone.0054146","article-title":"Tropisms of AAV for subretinal delivery to the neonatal mouse retina and its application for in vivo rescue of developmental photoreceptor disorders","volume":"8","author":"Watanabe","year":"2013","journal-title":"PloS. One."},{"key":"B55","doi-asserted-by":"publisher","first-page":"e201","DOI":"10.1371\/journal.pmed.0030201","article-title":"Lentiviral expression of retinal guanylate cyclase-1 (RetGC1) restores vision in an avian model of childhood blindness","volume":"3","author":"Williams","year":"2006","journal-title":"PLoS Med."},{"key":"B56","doi-asserted-by":"publisher","first-page":"525","DOI":"10.1038\/364525a0","article-title":"Red light disrupts magnetic orientation of migratory birds","volume":"364","author":"Wiltschko","year":"1993","journal-title":"Nature"},{"key":"B57","doi-asserted-by":"publisher","first-page":"7364","DOI":"10.1038\/s41598-020-64429-y","article-title":"Protein-protein interaction of the putative magnetoreceptor cryptochrome 4 expressed in the avian retina","volume":"10","author":"Wu","year":"2020","journal-title":"Sci. Rep."},{"key":"B58","doi-asserted-by":"publisher","first-page":"535","DOI":"10.1038\/s41586-021-03618-9","article-title":"Magnetic sensitivity of cryptochrome 4 from a migratory songbird","volume":"594","author":"Xu","year":"2021","journal-title":"Nature"},{"key":"B59","doi-asserted-by":"publisher","first-page":"179","DOI":"10.1016\/j.omtm.2020.01.002","article-title":"Suprachoroidal and subretinal injections of AAV using transscleral microneedles for retinal gene delivery in nonhuman primates","volume":"16","author":"Yiu","year":"2020","journal-title":"Mol. Ther. Methods. Clin. Dev."},{"key":"B60","doi-asserted-by":"publisher","first-page":"1274","DOI":"10.1038\/nature08528","article-title":"Visual but not trigeminal mediation of magnetic compass information in a migratory bird","volume":"461","author":"Zapka","year":"2009","journal-title":"Nature"},{"key":"B61","doi-asserted-by":"publisher","first-page":"5722","DOI":"10.3390\/ijms20225722","article-title":"Gene therapy in retinal dystrophies","volume":"20","author":"Ziccardi","year":"2019","journal-title":"Int. J. Mol. Sci."}],"container-title":["Frontiers in Physiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphys.2025.1549585\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,3,19]],"date-time":"2025-03-19T07:12:22Z","timestamp":1742368342000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphys.2025.1549585\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,3,19]]},"references-count":61,"alternative-id":["10.3389\/fphys.2025.1549585"],"URL":"https:\/\/doi.org\/10.3389\/fphys.2025.1549585","relation":{},"ISSN":["1664-042X"],"issn-type":[{"value":"1664-042X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,3,19]]},"article-number":"1549585"}}