Centriolar Protein C2cd3 Is Required for Craniofacial Development.

Ching-Fang Chang,Yanfen Yang,Samantha A Brugmann,Kari M Brown

doi:10.3389/fcell.2021.647391

Abstract

The primary cilium is a ubiquitous, microtubule-based cellular organelle. Primary cilia dysfunction results in a group of disorders termed ciliopathies. C2 domain containing 3 centriole elongation regulator (C2cd3), encodes a centriolar protein essential for ciliogenesis. Mutations in human C2CD3 are associated with the human ciliopathy Oral-Facial-Digital syndrome type 14 (OFD14). In order to better understand the etiology of ciliopathies including OFD14, we generated numerous murine models targeting C2cd3. Initial analysis revealed several tissue-specific isoforms of C2cd3, and while the loss of C2cd3 has previously been reported to result in exencephaly, tight mesencephalic flexure, pericardial edema, abnormal heart looping and a twisted body axis, further analysis revealed that genetic background may also contribute to phenotypic variation. Additional analyses of a conditional allelic series targeting C-terminal PKC-C2 domains or the N-terminal C2CD3N-C2 domain of C2cd3 revealed a variable degree of phenotypic severity, suggesting that while the N-terminal C2CD3N-C2 domain was critical for early embryonic development as a whole, there was also a craniofacial specific role for the C2CD3N-C2 domains. Together, through generation of novel models and evaluation of C2cd3 expression, these data provide valuable insight into mechanisms of pathology for craniofacial ciliopathies that can be further explored in the future.

Highlights

The primary cilium is a cellular organelle comprised of a microtubule-based axoneme extending from the cell surface, and a basal body that resides internally at the base of axoneme
Despite an accepted role in ciliogenesis, C2cd3 expression has not been well documented during embryogenesis or craniofacial development
C2cd3 expression was maintained later in development in both epithelial and mesenchymal tissues, including the lateral ganglionic eminence and ventricular zone of developing neocortex, perichondrium of developing cranial bones, palatal epithelium, oral epithelium, and mesenchyme surrounding Meckel’s cartilage at E14.5 (Figure 1E). These results suggested that C2cd3 expression was dynamic throughout embryonic and craniofacial development

Summary

Introduction

The primary cilium is a cellular organelle comprised of a microtubule-based axoneme extending from the cell surface, and a basal body that resides internally at the base of axoneme. There are 26 known ciliopathies, 25 predicted ciliopathies and another 400 human diseases considered possible ciliopathies that have yet to be classified (Schock and Brugmann, 2017). Ciliopathies often present with pleiotropic phenotypes including renal disease, retinal degeneration, obesity, skeletal dysplasia, and craniofacial anomalies (Reiter and Leroux, 2017), 30% of ciliopathies are primarily classified by their craniofacial phenotypes. Craniofacial ciliopathies are most frequently defined by the combinatorial presentation of cleft lip/palate, craniosynostosis, hypertelorism, and micrognathia (Schock and Brugmann, 2017). Backcrossed C57BL/6J F4 48 Phenotype Outcrossed Backcrossed. Tight mesencephalic flexure Abnormal heart looping Twisted body axis Pericardial edema CD1 (n = 10).

Methods

Results

Conclusion