{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,2]],"date-time":"2026-03-02T17:09:24Z","timestamp":1772471364570,"version":"3.50.1"},"reference-count":30,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2026,3,2]],"date-time":"2026-03-02T00:00:00Z","timestamp":1772409600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Hungarian National Research, Development and Innovation Office","award":["RRF-2.3.1-21-2022-00007"],"award-info":[{"award-number":["RRF-2.3.1-21-2022-00007"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomolecules"],"abstract":"<jats:p>This study aimed to establish a model for investigating X chromosome inactivation using transgenic mouse strains expressing green fluorescent protein (GFP). The D4\/XGFP-Tg (XGFP) strain carries the GFP transgene on the X chromosome; therefore, due to random X chromosome inactivation, female offspring from crosses between XGFP males and CD-1 females exhibit mosaic GFP expression. In contrast, the B5\/EGFP-Tg (EGFP) strain harbours autosomal integration of the same reporter construct, resulting in uniform GFP expression in progenies. Analysis of CD-1 \u00d7 XGFP attached blastocysts revealed strong GFP expression in giant trophoblast cells and primordial germ cells (PGCs) at E6.5, demonstrating paternal X-chromosome reactivation. In 14.5-day-old CD-1 \u00d7 XGFP female embryos and CD-1 \u00d7 EGFP embryos, intense CAG promoter-driven GFP signals were detected in the brain, heart, gonads, somites, and limbs. In line with random X-chromosome inactivation, only 56% of embryonic fibroblast cells, derived from CD-1 \u00d7 XGFP female embryos, exhibited GFP expression. These findings validate that CD-1 \u00d7 XGFP mice represent a valuable in vivo model for studying X chromosome inactivation during early embryonic development and PGC specification. Furthermore, CD-1 \u00d7 XGFP embryonic fibroblasts represent a valuable in vitro model for investigating the molecular mechanisms governing X-chromosome activation and inactivation.<\/jats:p>","DOI":"10.3390\/biom16030375","type":"journal-article","created":{"date-parts":[[2026,3,2]],"date-time":"2026-03-02T16:06:59Z","timestamp":1772467619000},"page":"375","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["X-Linked EGFP Reporter as a Tool to Examine X-Chromosome Inactivation in Mouse Embryos and Embryonic Fibroblasts"],"prefix":"10.3390","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6764-7384","authenticated-orcid":false,"given":"Martin","family":"Urb\u00e1n","sequence":"first","affiliation":[{"name":"Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Szent-Gy\u00f6rgyi Albert Str. 4, 2100 G\u00f6d\u00f6ll\u0151, Hungary"},{"name":"Agribiotechnology and Precision Breeding for Food Security National Laboratory, 2100 G\u00f6d\u00f6ll\u0151, Hungary"},{"name":"Institute of Molecular Life Sciences, Center of Excellence of The Hungarian Academy of Sciences, HUN-REN Research Centre for Natural Sciences, 1117 Budapest, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8636-3624","authenticated-orcid":false,"given":"Andr\u00e1s","family":"Ecker","sequence":"additional","affiliation":[{"name":"Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Szent-Gy\u00f6rgyi Albert Str. 4, 2100 G\u00f6d\u00f6ll\u0151, Hungary"},{"name":"Agribiotechnology and Precision Breeding for Food Security National Laboratory, 2100 G\u00f6d\u00f6ll\u0151, Hungary"},{"name":"Institute of Aquaculture and Environmental Safety, Hungarian University of Agriculture and Life Sciences, Szent-Gy\u00f6rgyi Albert Str. 4, 2100 G\u00f6d\u00f6ll\u0151, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Roland Imre","family":"T\u00f3th","sequence":"additional","affiliation":[{"name":"Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Szent-Gy\u00f6rgyi Albert Str. 4, 2100 G\u00f6d\u00f6ll\u0151, Hungary"},{"name":"Agribiotechnology and Precision Breeding for Food Security National Laboratory, 2100 G\u00f6d\u00f6ll\u0151, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0716-6113","authenticated-orcid":false,"given":"Bence","family":"L\u00e1z\u00e1r","sequence":"additional","affiliation":[{"name":"Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Szent-Gy\u00f6rgyi Albert Str. 4, 2100 G\u00f6d\u00f6ll\u0151, Hungary"},{"name":"Agribiotechnology and Precision Breeding for Food Security National Laboratory, 2100 G\u00f6d\u00f6ll\u0151, Hungary"},{"name":"National Centre for Biodiversity and Gene Conservation, 2100 G\u00f6d\u00f6ll\u0151, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Szil\u00e1rd","family":"Bod\u00f3","sequence":"additional","affiliation":[{"name":"Department of Animal Husbandry Sciences, Hungarian University of Agriculture and Life Sciences, 2100 G\u00f6d\u00f6ll\u0151, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7720-4720","authenticated-orcid":false,"given":"Elen","family":"G\u00f3cza","sequence":"additional","affiliation":[{"name":"Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Szent-Gy\u00f6rgyi Albert Str. 4, 2100 G\u00f6d\u00f6ll\u0151, Hungary"},{"name":"Agribiotechnology and Precision Breeding for Food Security National Laboratory, 2100 G\u00f6d\u00f6ll\u0151, Hungary"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1186\/jbiol95","article-title":"X-Chromosome Inactivation: The Molecular Basis of Silencing","volume":"7","author":"Panning","year":"2008","journal-title":"J. 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