{ "abstract": "The ability to monitor the proliferative status of live cells both in vitro and in vivo over time has revolutionised our understanding of development, growth and disease. This was first made possible by fluorescent ubiquitination-based cell cycle indicator (Fucci) technology, which distinguishes specific cell cycle phases through the reciprocal degradation of fluorescently tagged, truncated forms of human CDT1 and GMNN proteins. Fucci genetic systems have been successfully implemented in transgenic mice, zebrafish, and axolotls. To date, no viable, stably expressing Fucci line has been developed in an avian species. Although a range of continuously improving Fucci constructs have been developed in recent years, existing in vivo Fucci models remain limited because they rely on older reporter technology that fails to distinguish cells in S, G2, and M phases or to label cells in early G1. As a result, these models can be challenging to interpret and their utility for continuous cell tracking and precise analysis of cell-cycle dynamics is limited. Here, we introduce FuChi, a multicistronic Fucci-expressing chicken line incorporating a newly optimised reporter construct composed of an mCerulean-tagged histone H1.0 linker protein fused via a self-cleaving 2A peptide to the tandem Fucci(CA)2 cell cycle biosensor, with additional epitope tags included for detection in fixed tissues. We show that this system accurately discriminates and permits tracking of cells in G1, S, G2, and M phases both in vitro and in vivo, enabling faithful visualisation of cell cycle status in intact tissues and organs. Using FuChi embryos, we mapped proliferation dynamics across developing tissues, analysed cell cycle states of migrating cells, and performed live imaging of early embryos. These latter experiments revealed that transition from S phase may be a key morphogenetic event during gastrulation as mesendoderm cells egress from the primitive streak to form embryonic structures including the prechordal plate. Pairing this advanced reporter with the intrinsic experimental advantages of the chicken embryo positions FuChi as a premier in vivo system for studying cell-cycle kinetics in development, delivering clear technological improvements over current Fucci models. FuChi chickens provide a powerful new resource for studying embryonic development, organ growth, tissue homeostasis, disease processes, and infection responses.\n\nFucci genetic systems are commonly used to monitor cell proliferation in living cells, but no stably expressing Fucci line has been developed in an avian species. This study develops FuChi, the first avian Fucci reporter line that enables precise cell cycle tracking during embryonic development.", "abstract_shown": true, "affiliations": [ "The Roslin Institute & R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom.", "Roslin Institute Chicken Embryology (RICE) Group, The Roslin Institute & R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom.", "Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, United Kingdom.", "Faculty of Life Sciences, University of Dundee, Dundee, United Kingdom.", "Gurdon Institute, University of Cambridge, Cambridge, United Kingdom.", "Division of Physiology and Climatology, ICAR-Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India.", "Laboratory for Cell Function Dynamics, RIKEN Center for Brain Science, Wako, Saitama, Japan." ], "article_type": "Methods and Resources", "arxiv": null, "author_total": 24, "authors": [ { "affs": [ 0, 1 ], "name": "Zoe R Sudderick" }, { "affs": [ 2 ], "name": "Tiernan Briggs" }, { "affs": [ 3 ], "name": "Shirooza Mubarak" }, { "affs": [ 2 ], "name": "Melinda Van Kerckvoorde" }, { "affs": [ 4 ], "name": "Ana R Hernandez Rodriguez" }, { "affs": [ 0, 1, 5 ], "name": "Sudeepta K Panda" }, { "affs": [ 0, 1 ], "name": "Jon Riddell" }, { "affs": [ 0, 1 ], "name": "Cameron Batho-Samblas" }, { "affs": [ 0, 1 ], "name": "Lorna Taylor" }, { "affs": [ 0, 1 ], "name": "Lynn McTeir" }, { "affs": [ 0, 1 ], "name": "Dominique Meunier" }, { "affs": [ 0, 1 ], "name": "Amy Findlay" }, { "affs": [ 0, 1 ], "name": "Flossie S Roberts" }, { "affs": [ 0 ], "name": "Anna Raper" }, { "affs": [ 6 ], "name": "Asako Sakaue-Sawano" }, { "affs": [ 6 ], "name": "Atsushi Miyawaki" }, { "affs": [ 0, 1 ], "name": "Joe Rainger" }, { "affs": [ 0, 1 ], "name": "Jeffrey J Schoenebeck" }, { "affs": [ 3 ], "name": "Cornelis J Weijer", "orcid": "0000-0003-2192-8150" }, { "affs": [ 0, 1 ], "name": "Mike J McGrew" }, { "affs": [ 0, 1 ], "name": "Denis J Headon" }, { "affs": [ 0, 1 ], "name": "Megan G Davey" }, { "affs": [ 2 ], "name": "Richard L Mort", "orcid": "0000-0002-3566-8217" }, { "affs": [ 0, 1 ], "name": "James D Glover" } ], "bibtex": "https://research.draconitic.com/paper/0g8snc3cy4yr9.bib", "cited_by": 0, "doi": "10.1371/journal.pbio.3004036", "fulltext_url": "https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3004036", "id": "0g8snc3cy4yr9", "issns": [ "1545-7885", "1544-9173" ], "landing_url": "https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3004036", "language": "eng", "licence": "CC-BY", "licence_label": "CC BY", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "openalex", "1312|Developmental Biology and Gene Regulation" ], [ "plos", "/Biology and life sciences/Cell biology/Cell processes/Cell cycle and cell division" ], [ "plos", "/Biology and life sciences/Cell biology/Cell processes/Cell cycle and cell division/Synthesis phase" ], [ "plos", "/Biology and life sciences/Developmental biology/Embryology/Embryos" ], [ "plos", "/Biology and life sciences/Developmental biology/Organism development/Organogenesis/Somites" ], [ "plos", "/Biology and life sciences/Organisms/Eukaryota/Animals/Vertebrates/Amniotes/Birds" ], [ "plos", "/Biology and life sciences/Organisms/Eukaryota/Animals/Vertebrates/Amniotes/Birds/Fowl/Gamefowl/Chickens" ], [ "plos", "/Biology and life sciences/Organisms/Eukaryota/Animals/Vertebrates/Amniotes/Birds/Poultry/Chickens" ], [ "plos", "/Biology and life sciences/Zoology/Animals/Vertebrates/Amniotes/Birds" ], [ "plos", "/Biology and life sciences/Zoology/Animals/Vertebrates/Amniotes/Birds/Fowl/Gamefowl/Chickens" ], [ "plos", "/Biology and life sciences/Zoology/Animals/Vertebrates/Amniotes/Birds/Poultry/Chickens" ], [ "plos", "/Engineering and technology/Equipment/Detectors/Biosensors" ], [ "plos", "/Research and analysis methods/Animal studies/Experimental organism systems/Animal models/Chicken models" ] ], "openalex": "W7221124268", "pdf_url": "https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.3004036&type=printable", "pmcid": "PMC13705591", "pmid": "42853865", "published": "2026-10-09", "publisher": "Public Library of Science", "ris": "https://research.draconitic.com/paper/0g8snc3cy4yr9.ris", "sources": [ { "first_seen": "2026-10-30T12:17:30Z", "native_id": "10.1371/journal.pbio.3004036", "source": "plos", "url": "https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3004036" }, { "first_seen": "2026-10-30T12:18:12Z", "native_id": "MED:42853865", "source": "europepmc", "url": "https://europepmc.org/article/MED/42853865" } ], "subjects": [ { "field": "biology", "origin": "plos:cell biology", "subfield": "cell-biology" }, { "field": "biology", "origin": "plos:developmental biology", "subfield": "developmental-biology" }, { "field": "biology", "origin": "plos:zoology", "subfield": "zoology-behaviour" } ], "title": "FuChi is a cell cycle biosensor for tracking cell cycle dynamics during avian development", "title_text": "FuChi is a cell cycle biosensor for tracking cell cycle dynamics during avian development", "type": "peer-reviewed", "updated_at": "2026-10-30T12:18:12Z", "url": "https://research.draconitic.com/paper/0g8snc3cy4yr9", "venue": "PLOS Biology", "versions": [] }