Marie Landova Sulcova1,2, Oldrich Zahradnicek3, Jana Dumkova4, Hana Dosedelova1, Jan Krivanek4, Marek Hampl1,2, Michaela Kavkova5, Tomas Zikmund5, Martina Gregorovicova6,7, David Sedmera6,7, Jozef Kaiser5, Abigail S Tucker3,8, Marcela Buchtova1,2. 1. Laboratory of Molecular Morphogenesis, Institute of Animal Physiology and Genetics, Czech Academy of Science, Brno, Czech Republic. 2. Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic. 3. Institute of Experimental Medicine, Czech Academy of Science, Prague, Czech Republic. 4. Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic. 5. CEITEC-Central European Institute of Technology, University of Technology, Brno, Czech Republic. 6. Institute of Anatomy, Medical Faculty, Charles University, Prague, Czech Republic. 7. Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic. 8. Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London, UK.
Abstract
BACKGROUND: In mammals, odontogenesis is regulated by transient signaling centers known as enamel knots (EKs), which drive the dental epithelium shaping. However, the developmental mechanisms contributing to formation of complex tooth shape in reptiles are not fully understood. Here, we aim to elucidate whether signaling organizers similar to EKs appear during reptilian odontogenesis and how enamel ridges are formed. RESULTS: Morphological structures resembling the mammalian EK were found during reptile odontogenesis. Similar to mammalian primary EKs, they exhibit the presence of apoptotic cells and no proliferating cells. Moreover, expression of mammalian EK-specific molecules (SHH, FGF4, and ST14) and GLI2-negative cells were found in reptilian EK-like areas. 3D analysis of the nucleus shape revealed distinct rearrangement of the cells associated with enamel groove formation. This process was associated with ultrastructural changes and lipid droplet accumulation in the cells directly above the forming ridge, accompanied by alteration of membranous molecule expression (Na/K-ATPase) and cytoskeletal rearrangement (F-actin). CONCLUSIONS: The final complex shape of reptilian teeth is orchestrated by a combination of changes in cell signaling, cell shape, and cell rearrangement. All these factors contribute to asymmetry in the inner enamel epithelium development, enamel deposition, ultimately leading to the formation of characteristic enamel ridges.
BACKGROUND: In mammals, odontogenesis is regulated by transient signaling centers known as enamel knots (EKs), which drive the dental epithelium shaping. However, the developmental mechanisms contributing to formation of complex tooth shape in reptiles are not fully understood. Here, we aim to elucidate whether signaling organizers similar to EKs appear during reptilian odontogenesis and how enamel ridges are formed. RESULTS: Morphological structures resembling the mammalian EK were found during reptile odontogenesis. Similar to mammalian primary EKs, they exhibit the presence of apoptotic cells and no proliferating cells. Moreover, expression of mammalian EK-specific molecules (SHH, FGF4, and ST14) and GLI2-negative cells were found in reptilian EK-like areas. 3D analysis of the nucleus shape revealed distinct rearrangement of the cells associated with enamel groove formation. This process was associated with ultrastructural changes and lipid droplet accumulation in the cells directly above the forming ridge, accompanied by alteration of membranous molecule expression (Na/K-ATPase) and cytoskeletal rearrangement (F-actin). CONCLUSIONS: The final complex shape of reptilian teeth is orchestrated by a combination of changes in cell signaling, cell shape, and cell rearrangement. All these factors contribute to asymmetry in the inner enamel epithelium development, enamel deposition, ultimately leading to the formation of characteristic enamel ridges.
Authors: M Kavková; M Šulcová; J Dumková; O Zahradníček; J Kaiser; A S Tucker; T Zikmund; M Buchtová Journal: Sci Rep Date: 2020-12-16 Impact factor: 4.379
Authors: Michaela Kavková; Marie Šulcová; Tomáš Zikmund; Martin Pyszko; Jozef Kaiser; Marcela Buchtová Journal: Gigascience Date: 2022-03-07 Impact factor: 6.524
Authors: Michaela Kavkova; Tomas Zikmund; Annu Kala; Jakub Salplachta; Stephanie L Proskauer Pena; Josef Kaiser; Karel Jezek Journal: Sci Rep Date: 2021-03-16 Impact factor: 4.379