| Affiliation: | 1. Institute for Biology and Sächsischer Inkubator für klinische Translation (TRM/SIKT), University of Leipzig, 04103 Leipzig, Germany;2. Life & Medical Sciences Institute (LIMES), University of Bonn, 53115 Bonn, Germany;3. Max Planck Institute for Biophysical Chemistry, Electron Microscopy Group, 37077 Göttingen, Germany;1. Institute of Biology and Translational Center for Regenerative Medicine, University of Leipzig, Leipzig, Germany;2. Department of Dermatology, Medical Center-University of Freiburg, Freiburg, Germany;3. Department of Dermatology and Allergology, University Medical Center Giessen and Marburg, Justus Liebig University, Giessen, Germany;1. Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221 005, India;2. Department of Zoology, The University of Burdwan, Golapbag, Burdwan, 713104, India;1. Department of Biochemistry and Molecular Biophysics, Kansas State University, 141 Chalmers Hall, Manhattan, KS 66506, USA;2. Department of Applied Biology, Chonnam National University, Gwangju 500-757, Republic of Korea;3. Interfaculty Institute for Cell Biology, Animal Genetics, University of Tübingen, Tübingen, Germany;4. Department of Medicine, University of Massachusetts, Worcester, MA 01605, USA;5. Department of Entomology, Kansas State University, 123 W. Waters Hall, Manhattan, KS 66506, USA |
| Abstract: | The architecture of the outer body wall cuticle is fundamental to protect arthropods against invading pathogens and numerous other harmful stresses. Such robust cuticles are formed by parallel running chitin microfibrils. Molting and also local wounding leads to dynamic assembly and disassembly of the chitin-matrix throughout development. However, the underlying molecular mechanisms that organize proper chitin-matrix formation are poorly known. Recently we identified a key region for cuticle thickening at the apical cell surface, the cuticle assembly zone, where Obstructor-A (Obst-A) coordinates the formation of the chitin-matrix. Obst-A binds chitin and the deacetylase Serpentine (Serp) in a core complex, which is required for chitin-matrix maturation and preservation. Here we present evidence that Chitinase 2 (Cht2) could be essential for this molecular machinery. We show that Cht2 is expressed in the chitin-matrix of epidermis, trachea, and the digestive system. There, Cht2 is enriched at the apical cell surface and the dense chitin-matrix. We further show that in Cht2 knockdown larvae the assembly zone is rudimentary, preventing normal cuticle formation and pore canal organization. As sequence similarities of Cht2 and the core complex proteins indicate evolutionarily conserved molecular mechanisms, our findings suggest that Cht2 is involved in chitin formation also in other insects. |
