CORDIS

Chaetae, the chitinous bristles, of segmented worms are without a doubt one of their most characteristic features. A single cell, called chaetoblast, forms these complex extracellular structures, through an intricate interplay of the cytoskeleton and controlled polymerization of chitin. I have been investigating this fascinating system and published a series of papers describing the process of chaetal formation in various annelids using serial TEM and histology. With this proposed project I will combine my previous training and take the next logical step in the study of chaetogenesis; by investigating the molecular underpinnings of chaetal formation, focusing on chitin synthases. Chitin is one of the most dominant biopolymers in nature and a key building block of diverse extracellular structures. The bone eating worm Osedax japonicus will be the main focus of this study. Its fast and simple chaetal development, together with the drastic anatomical difference between males and females, renders it a perfect model to link the differential expression of chitin synthases to any relevant point of chaetogenesis that can be ultrastructurally profiled. Genetically well-examined annelid Capitella teleta will serve to test the functional genetics of chitin synthases using CRISPR/CAS9. This integrative approach combining advanced microscopical techniques with cutting-edge transcriptomics will result in a giant leap towards revealing the genetic network regulating chaetogenesis. I will be laying the groundwork to fully understand how morphologically complex, chitinous hard structures can be formed by a single cell. Elucidating the molecular and cellular mechanisms behind this process, that is comparable to a biological 3D printer, is highly relevant for not only annelid researchers but also to a broader scientific community studying biomechanics, biomineralization, cell-biology and even bionics.