{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T21:19:24Z","timestamp":1792790364844,"version":"4.5.0"},"posted":{"date-parts":[[2026,9,17]]},"group-title":"Neuroscience","reference-count":45,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T00:00:00Z","timestamp":1789603200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"LND Famiglie Italiane Odv"},{"award":["R01 NS119758"],"award-info":[{"award-number":["R01 NS119758"]}],"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]},{"name":"University of Pennsylvania Orphan Disease Center in partnership with the Love Never Sinks Organization","id":[{"id":"https:\/\/ror.org\/00b30xv10","id-type":"ROR","asserted-by":"crossref"}]},{"name":"Dutch Research Council","award":["NWA.1160.18.320"],"award-info":[{"award-number":["NWA.1160.18.320"]}],"id":[{"id":"https:\/\/ror.org\/04jsz6e67","id-type":"ROR","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,9,17]]},"abstract":"<jats:title>Summary<\/jats:title>\n                <jats:p>\n                  A central challenge in genetic neurodevelopmental disorders is determining the developmental windows, brain regions, and cell lineages that are affected by gene dysfunction, and whether the resulting pathology remains reversible. The defined genotype\u2013phenotype relationship in Lesch\u2013Nyhan disease (LND), a monogenic disorder caused by pathogenic variants in\n                  <jats:italic>HPRT1<\/jats:italic>\n                  and subsequent deficiency of the purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HGprt), provides a well-characterized disease context for such mechanistic investigations.\n                <\/jats:p>\n                <jats:p>\n                  We present a new conditional\n                  <jats:italic>Hprt1<\/jats:italic>\n                  mouse model carrying a loxP-flanked mCherry and transcriptional stop cassette, permitting Cre-driver-dependent analysis of spatially and temporally controlled restoration of endogenous\n                  <jats:italic>Hprt1<\/jats:italic>\n                  expression during brain development.\n                <\/jats:p>\n                <jats:p>\n                  <jats:italic>Hprt1<\/jats:italic>\n                  reactivation was confirmed at the genomic, transcriptional, and biochemical levels. Using the ubiquitous tamoxifen-inducible CAG-CreER driver, a single maternal tamoxifen dose at embryonic day (E)8.5 restored whole-brain\n                  <jats:italic>Hprt1<\/jats:italic>\n                  mRNA expression and HGprt enzyme activity in E14.5 embryos to 72.4% and 13.4% of wild-type levels, respectively. Postnatal exposure through lactation during maternal treatment from postnatal day (P)0 to P4 yielded whole-brain HGprt activity equivalent to 28.3% of the WT level at P17. However, ligand-independent CAG-CreER activity and treatment-associated reproductive and developmental complications precluded extended longitudinal rescue studies with this Cre-driver.\n                <\/jats:p>\n                <jats:p>\n                  Developmentally regulated Wnt1-Cre2 activity, from E8 onwards, provided an alternative approach that permitted analysis through P60. Although the Wnt1 lineage constitutes only a fraction of the developing brain, Cre-dependent reactivation produced detectable HGprt activity in the forebrain, midbrain, and hindbrain. RNA fluorescent\n                  <jats:italic>in situ<\/jats:italic>\n                  hybridization (FISH) detected spatially distributed\n                  <jats:italic>Hprt1<\/jats:italic>\n                  reactivation in the midbrain and prefrontal cortex at E14.5 and across multiple midbrain, cortical, and subcortical regions at P60.\n                <\/jats:p>\n                <jats:p>\n                  These findings establish the conditional\n                  <jats:italic>\n                    Hprt1\n                    <jats:sup>tm1.1(LoxP-mCherry-Stop-LoxP)Vsr<\/jats:sup>\n                  <\/jats:italic>\n                  mouse as a model for investigating when and where\n                  <jats:italic>Hprt1<\/jats:italic>\n                  restoration could rescue abnormal brain development, while demonstrating that Cre-driver properties determine experimental specificity and longitudinal feasibility. Beyond LND, this conditional reactivation strategy provides an approach for defining developmental windows of reversibility and lineage-specific requirements for gene restoration in monogenic neurodevelopmental disorders.\n                <\/jats:p>","DOI":"10.64898\/2026.09.15.751558","type":"posted-content","created":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T12:25:14Z","timestamp":1789647914000},"source":"Crossref","is-referenced-by-count":0,"title":["A new conditional mouse model for Cre-mediated restoration of\n                  <i>Hprt1<\/i>\n                  expression during brain development"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5738-156X","authenticated-orcid":false,"given":"R.J.","family":"Havelaar","sequence":"first","affiliation":[{"name":"Section Neurobiology, Donders Center for Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, The Netherlands"},{"name":"Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"Fuss","sequence":"additional","affiliation":[{"name":"Neurodevelopmental Genetics, Medical Faculty, Institute of Reconstructive Neurobiology, University of Bonn, Bonn, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1898-4891","authenticated-orcid":false,"given":"S.","family":"Blaess","sequence":"additional","affiliation":[{"name":"Neurodevelopmental Genetics, Medical Faculty, Institute of Reconstructive Neurobiology, University of Bonn, Bonn, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2116-5456","authenticated-orcid":false,"given":"S.M.","family":"Kolk","sequence":"additional","affiliation":[{"name":"Section Neurobiology, Donders Center for Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9896-3416","authenticated-orcid":false,"given":"J.E.","family":"Visser","sequence":"additional","affiliation":[{"name":"Section Neurobiology, Donders Center for Neuroscience, Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen, The Netherlands"},{"name":"Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands"},{"name":"Department of Neurology, Amphia Hospital, Breda, The Netherlands"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026092113250756000_2026.09.15.751558v1.1","doi-asserted-by":"publisher","DOI":"10.1007\/s11248-019-00177-8"},{"key":"2026092113250756000_2026.09.15.751558v1.2","doi-asserted-by":"publisher","DOI":"10.1186\/s12864-017-3674-x"},{"key":"2026092113250756000_2026.09.15.751558v1.3","doi-asserted-by":"publisher","DOI":"10.1016\/j.stemcr.2021.06.003"},{"key":"2026092113250756000_2026.09.15.751558v1.4","doi-asserted-by":"publisher","DOI":"10.1002\/cne.22710"},{"key":"2026092113250756000_2026.09.15.751558v1.5","doi-asserted-by":"publisher","DOI":"10.3389\/fnana.2017.00067"},{"key":"2026092113250756000_2026.09.15.751558v1.6","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-024-44997-7"},{"key":"2026092113250756000_2026.09.15.751558v1.7","doi-asserted-by":"publisher","DOI":"10.1016\/s0960-9822(07)00562-3"},{"key":"2026092113250756000_2026.09.15.751558v1.8","doi-asserted-by":"publisher","DOI":"10.1080\/01677063.2022.2129632"},{"key":"2026092113250756000_2026.09.15.751558v1.9","doi-asserted-by":"publisher","DOI":"10.1002\/dvg.23468"},{"key":"2026092113250756000_2026.09.15.751558v1.10","unstructured":"Dong, Hong Wei . (2008). The Allen reference atlas: A digital color brain atlas of the C57Bl\/6J male mouse (pp. ix, 366). John Wiley & Sons, Inc."},{"key":"2026092113250756000_2026.09.15.751558v1.11","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-019-10239-4"},{"key":"2026092113250756000_2026.09.15.751558v1.12","doi-asserted-by":"publisher","DOI":"10.1016\/j.ymgme.2014.05.012"},{"key":"2026092113250756000_2026.09.15.751558v1.13","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M111.317701"},{"key":"2026092113250756000_2026.09.15.751558v1.14","doi-asserted-by":"publisher","DOI":"10.1016\/j.ymgme.2014.11.001"},{"key":"2026092113250756000_2026.09.15.751558v1.15","doi-asserted-by":"publisher","DOI":"10.1002\/ana.24191"},{"key":"2026092113250756000_2026.09.15.751558v1.16","doi-asserted-by":"publisher","DOI":"10.1038\/mt.2009.178"},{"key":"2026092113250756000_2026.09.15.751558v1.17","doi-asserted-by":"publisher","DOI":"10.1006\/dbio.2002.0597"},{"key":"2026092113250756000_2026.09.15.751558v1.18","doi-asserted-by":"publisher","DOI":"10.7554\/eLife.46181"},{"key":"2026092113250756000_2026.09.15.751558v1.19","doi-asserted-by":"publisher","DOI":"10.1016\/0887-8994(86)90032-9"},{"key":"2026092113250756000_2026.09.15.751558v1.20","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0047794"},{"key":"2026092113250756000_2026.09.15.751558v1.21","doi-asserted-by":"publisher","DOI":"10.1093\/brain\/awl056"},{"key":"2026092113250756000_2026.09.15.751558v1.22","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.14-03-01164.1994"},{"key":"2026092113250756000_2026.09.15.751558v1.23","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0016572"},{"key":"2026092113250756000_2026.09.15.751558v1.24","doi-asserted-by":"publisher","DOI":"10.3389\/fncel.2021.648570"},{"key":"2026092113250756000_2026.09.15.751558v1.25","unstructured":"Kim, Sung-Eun , Robles-Lopez, Karla , Cao, Xuanye , Liu, Kristyn , Chothani, Pooja J. , Bhavani, Nikitha , Rahman, Lauren , Mukhopadhyay, Saikat , Wlodarczyk, Bogdan J. , & Finnell, Richard H . (2021). Wnt1"},{"key":"2026092113250756000_2026.09.15.751558v1.26","doi-asserted-by":"publisher","DOI":"10.3389\/fgene.2021.761418"},{"key":"2026092113250756000_2026.09.15.751558v1.27","doi-asserted-by":"publisher","DOI":"10.1038\/nrm.2017.103"},{"key":"2026092113250756000_2026.09.15.751558v1.28","doi-asserted-by":"publisher","DOI":"10.1007\/s11248-015-9905-5"},{"key":"2026092113250756000_2026.09.15.751558v1.29","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM198111053051902"},{"key":"2026092113250756000_2026.09.15.751558v1.30","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-8749.2010.03786.x"},{"key":"2026092113250756000_2026.09.15.751558v1.31","doi-asserted-by":"publisher","DOI":"10.1016\/0009-8981(86)90031-8"},{"key":"2026092113250756000_2026.09.15.751558v1.32","doi-asserted-by":"publisher","DOI":"10.1242\/dev.119.1.247"},{"key":"2026092113250756000_2026.09.15.751558v1.33","doi-asserted-by":"publisher","DOI":"10.1002\/bdr2.1628"},{"key":"2026092113250756000_2026.09.15.751558v1.34","doi-asserted-by":"publisher","DOI":"10.1007\/978-0-387-47093-1"},{"key":"2026092113250756000_2026.09.15.751558v1.35","doi-asserted-by":"publisher","DOI":"10.1038\/nature10098"},{"key":"2026092113250756000_2026.09.15.751558v1.36","doi-asserted-by":"publisher","DOI":"10.1172\/JCI80554"},{"key":"2026092113250756000_2026.09.15.751558v1.37","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0256299"},{"key":"2026092113250756000_2026.09.15.751558v1.38","doi-asserted-by":"publisher","DOI":"10.1177\/0023677219856918"},{"key":"2026092113250756000_2026.09.15.751558v1.39","doi-asserted-by":"publisher","DOI":"10.3389\/neuro.02.024.2009"},{"issue":"5","key":"2026092113250756000_2026.09.15.751558v1.40","first-page":"709","article-title":"Mutation of murine Sox4 untranslated regions results in partially penetrant perinatal lethality","volume":"28","year":"2014","journal-title":"In Vivo"},{"key":"2026092113250756000_2026.09.15.751558v1.41","doi-asserted-by":"publisher","DOI":"10.1016\/0092-8674(87)90664-7"},{"key":"2026092113250756000_2026.09.15.751558v1.42","doi-asserted-by":"publisher","DOI":"10.1007\/s00018-022-04326-x"},{"key":"2026092113250756000_2026.09.15.751558v1.43","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.93.11.5539"},{"key":"2026092113250756000_2026.09.15.751558v1.44","doi-asserted-by":"publisher","DOI":"10.1007\/s11248-008-9237-9"},{"key":"2026092113250756000_2026.09.15.751558v1.45","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-4547(19980701)53:1<78::AID-JNR8>3.0.CO;2-G"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.64898\/2026.09.15.751558","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T20:25:27Z","timestamp":1790022327000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.64898\/2026.09.15.751558"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,17]]},"references-count":45,"URL":"https:\/\/doi.org\/10.64898\/2026.09.15.751558","relation":{},"subject":[],"published":{"date-parts":[[2026,9,17]]},"subtype":"preprint"}}