Abstract
The synaptonemal complex proteins, SCP1, SCP2, and SCP3, are components of the synaptonemal complex (SC), a meiosis-specific protein structure essential for synapsis of homologous chromosomes. Among these, at least SCP1 is ectopically expressed in some tumors, suggesting that SC proteins might belong to the cancer/testis antigens group. However, the role of SC proteins in tumorigenesis is still unknown. In this study, we investigated the tumorigenic function of another SC protein, SCP3. Several cancer cell lines deriving from various human tissues ectopically expressed SCP3. Forced expression of SCP3 in retinal pigmented epithelial cells resulted in reduction of growth rates. These cells frequently had one, three or four copies of chromosomes, suggesting that SCP3 induced aneuploidy. Moreover, these cells also showed hypersensitivity to ionizing radiation. Therefore, ectopic expression of an SC protein, SCP3, leads to genetic instability and could initiate tumorigenesis.
