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What do we work with?
We study early Xenopus frog embryos: a powerful model for developmental biology. 🐸

Why frogs?
Their embryos are large, develop outside the body, and are ideal for live imaging and experimental manipulation. 🔬

Why Xenopus?
Xenopus was the first reliable model used for human fertility testing (the Hogben test) and later became the most widely used amphibian model in biomedical research. 🧪

What do we study?
Neural tube formation, neural crest cell migration, and the signaling mechanisms that shape developing tissues.
And more. 🧠

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Want to discover more? Click the link to our short reportages on Czech Radio or Czech TV broadcasts (both in Czech), and the popular biology blog, The Node (in English).

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LAB HEAD

Name: Assist. Prof. Jakub “James” Harnos, Ph.D.
Office: Campus Bohunice, bldg. D36, rm 1S16
E-mail: harnos@sci.muni.cz
Telephone: +420 549 49 4465
ORCID ID: 0000-0002-0752-9260

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Scientific autobiography

My research explores how cells signal, move, and organize tissues during development.
After PhD training in Germany and postdoctoral work in New York on WNT/PCP signaling in Xenopus, I now run an independent lab at Masaryk University.

We use live embryos, advanced imaging, and molecular tools to address fundamental questions in developmental and disease biology. 🔬

🧬 Field: cellular signaling


🇨🇿/🇩🇪 PhD: Brno/Wurzburg (molecular signaling)
🇺🇸 Postdoc: New York (Xenopus, PCP)
🇨🇿 PI: Masaryk University since 2020 (Xenopus)

🔬 Approach: live imaging, biosensors, proteomics, Xenopus 🐸

 

Fellowships, Grants, and Awards 

*2026 – 2028: MUNI Junior Star (#MUNI/JS/1952/2025), Grant Agency of Masaryk University, Czechia

*2025 – 2026: MSCAfellow5_MUNI (#22_010/0003229), Czech MEYS, Czechia

*2024 – 2026: Grant in the Standard/Senior category (#24-10622S), Czech Science Foundation, Czechia

2023: Hemsley Fellowship (#203103), Xenopus course, Cold Spring Harbor Laboratories, NY, USA (declined due to family reasons)

2022 – 2024: Grant in the Standard/Senior category (#22-06405S), Czech Science Foundation, Czechia

2022 – 2024: Science & Humanities Award Junior (#MUNI/J/0004/2021), Grant Agency of Masaryk University, Czechia

2020: “Seal of Excellence” in MSCA-IF-2020 (#101028952), European Commission, Brussels

2018 – 2019: “Excellent Results” Grant (#MUNI/E/0533/2018), Grant Agency of Masaryk University, Czechia

2017 – 2017: EMBO Short-term Fellowship (#ASTF 687-2016), University of Wurzburg, Germany

2016 – 2016: Mobility program “Free mover”, University of Wurzburg, Germany

*Current funding

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OUR RESEARCH

Cells need to know where they are and where to go.
We study planar cell polarity (PCP) — the way cells align and coordinate their behavior across a tissue.

Polarity is usually seen as a simple directional guide. 🧭 We think it does much more.


A) Our research shows that polarity proteins can actively start major developmental events, such as neural tube formation, an early step in building the brain and spinal cord.

B) We are also interested in cell movement. Cells need extra energy to move, but what tells them to start producing it?
We propose that cell polarity works like a switch, turning on the energy and structural changes needed for migration.

In short: we study how polarity proteins actively drive cell behavior, using Xenopus embryos and cell models to watch these processes in real time.

Keywords

Planar polarity, neural tube formation, cell migration, bioenergetics, Xenopus embryos.

 

 

OUR PAPERS

  • Cell signaling in vertebrates (planar cell polarity signaling):
    • Radaszkiewicz KA, Radaszkiewicz TW, Kolářová P, Paclíková P, Gömöryová K, Novotná Š, Maia LA, Číhalová T, Le Y, Bárta T, Hanáková H, Hyšková A, Tripsianes K, Zdráhal Z, Winkler C, and Harnos J*.
      “PRICKLE3 protects VANGL proteins from CK1-mediated phosphorylation and RNF43-mediated degradation”.
      Commun Biol. 2025, doi: 10.1038/s42003-025-09422-9
    • Novotna S, Maia LA, Radaszkiewicz KA, Roudnicky P, and Harnos J*.
      “Linking planar polarity signaling to actomyosin contractility during vertebrate neurulation.”
      Open Biology, 2024, doi: 10.1098/rsob.240251
    • Radaszkiewicz KA, Sulcova M, Kohoutkova E, and Harnos J*.
      “The role of Prickle proteins in vertebrate development and pathogeny.”
      Molecular Cell Biochemistry, 2023, doi: 10.1007/s11010-023-04787-z
  • New aspects of vertebrate development:
    • Riesova B, Maia LA, Hesova R, Peskova N, Marsalek P, Blahova J, Lakdawala P, and Harnos J*.
      “Developmental toxicity of fluconazole and 1,2,4-triazole in Xenopus laevis.”
      Scientific Reports, 2025, doi: 10.1038/s41598-025-30992-5
    • Laznovsky J, Kavkova M, Reis A, Robovska-Havelkova P, Maia LA, Krivanek J, Zikmund T, Kaiser J, Buchtova M, and Harnos J*.
      “Unveiling vertebrate development dynamics in Xenopus laevis using micro-CT imaging.”
      GigaScience, 2024, doi: 10.1093/gigascience/giae037  
  • Studying in-cell DNA quadruplex structures using Xenopus oocytes:
    • Foldynova-Trantirkova S, Harnos J, Rynes J, Zlinska V, and Trantirek L.
      “In-cell NMR spectroscopy of nucleic acids: Basic concepts, practical aspects, and applications.”
      Progress in Nuclear Magnetic Resonance Spectroscopy, 2025, doi: 10.1016/j.pnmrs.2025.101560
    • Ghosh A, Harnos J, Stadlbauer P, Sponer J, Lenarcic Zivkovic M, and Trantirek L.
      “Structural basis of bis-quinolinium ligands binding to quadruplex-duplex hybrids from PIM1 oncogene.” 
      Nucleic Acids Research, 2025, doi: 10.1093/nar/gkaf894 
  • New methodology of DNA cloning:
    • Paclikova P, and Harnos J*. “Efficient cloning of linear DNA inserts (ECOLI) into plasmids using site-directed mutagenesis.”
      Scientific Reports, 2024, doi: 10.1038/s41598-024-72169-6  

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TEAM MEMBERS

  • Alumni
    • Alba Macipe Feito (2026; Erasmus student, a practical 4-month stay, University UFV in Madrid, Spain)
    • Ana Moreno Llorente (2026; Erasmus student, a practical 4-month stay, University UFV in Madrid, Spain)
    • Mgr. Marek Dokoupil (2023–2026; currently a Ph.D. student in Bohaciakova lab, MUNI, Czechia)
    • Mgr. Adela Zaoralkova (2025–2026; currently an embryologist in an IVF clinic, Czechia)
    • Mgr. Hana Suchankova (2024–2026; currently a Ph.D. student in Skoda lab, MUNI, Czechia)
    • Mgr. Kristyna Daniela Krutova (2024–2026; currently working in the pharma industry, Czechia)
    • Katarzyna Radaszkiewicz, Ph.D., M.Sc. (2022–2025; currently on maternity leave)
    • Mgr. Pavla Kolarova (2021–2025; currently a Ph.D. student in Buchtova lab, MUNI, Czechia)
    • Mgr. Aneta Poukova (2021–2025; currently a research assistant in Vacha lab, MUNI, Czechia)
    • Bc. Nela Leksova (2024–2025; currently a Master’s student in Psychology, MUNI, Czechia)
    • Mgr. Julie Netusilova (2022–2025; currently on maternity leave)
    • Mgr. Petra Paclikova, Ph.D. (2024; currently a postdoc in Tesina lab, MUNI, Czechia)
    • Ing. Mgr. Vendula Janouskova (2023–2024; currently a Ph.D. student, Prague, Czechia)
    • Mgr. Marie Sulcova, Ph.D. (2022–2023; currently a postdoc in Bohaciakova lab, MUNI, Brno)
    • Alba Hernandez Ramos (2022–2023; Erasmus student, a practical 10-month stay, University of Salamanca, Spain)
    • Mgr. Eliska Kohoutkova (2022–2023; currently a Ph.D. student at Vienna Biocenter, Austria)
    • Cristina Gonzalez Cuevas (2022; Erasmus student, a practical 3-month stay, University UFV in Madrid, Spain)
    • Belén Escalona Pulido (2022; Erasmus student, a practical 4-month stay, University UFV in Madrid, Spain)
    • Miriam Sanchez Calvo (2022; Erasmus student, a practical 4-month stay, University UFV in Madrid, Spain)

COLLABORATORS

Asia: Prof. Christoph Winkler (National University of Singapore, Singapore)

USA: Dr. Alice Reis (Columbia University, New York), Dr. Giovanna Collu (Icahn School of Medicine at Mount Sinai, New York)

Czechia: Assoc. Prof. Lukas Trantirek and Dr. Anirban Ghosh (CEITEC, Brno), Dr. Jan Masek (Charles University, Prague)

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We are actively recruiting talent from Bachelor’s and Master’s students

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Check our LinkedIn