HUGO (FNDC3A): a new gene overexpressed in human odontoblasts

Previously, we established a subtractive cDNA library enriched in odontoblast-specific genes and hypothesized that new, previously unidentified, markers would be present, associated with the odontoblast phenotype. In this paper, we report the first characterization of a new gene we have named HUGO, and its associated deduced protein sequence. This gene expression is under the control of two alternative promoters, resulting in the synthesis of two proteins, one of which, HUGO2, is included in the other, HUGO1. HUGO proteins are mainly composed of a proline-rich region at the N-terminus, 8 type III-fibronectin modules, and a transmembranous helix at the C-terminus. In odontoblasts, the proteins are located in Golgi vesicles. However, they display a broader expression pattern, since they are also expressed by nerve fibers in the dental pulp and other tissues (e.g., trachea, brain, kidney), as demonstrated by immunohistochemistry and qPCR, respectively. Their location in odontoblasts suggests a role in collagen and glycosaminoglycan synthesis.