Synaptonemal Complex Protein 3 (SCP3) is a component of the synaptonemal complex, which is a meiosis-specific proteinaceous structure required for the pairing and segregation of homologous chromosomes. SCP3 is considered a marker of meiosis. Expressed in germ cells in testis, SCP3 may have a negative affect on spermatogenesis. SCP3 is also expressed in the ovaries. Human SCP3 is a 236 amino acid protein with a centrally located nuclear localization signal (NLS) and two C-terminal coiled coil domains. Human SCP3 and mouse SCP3 share 71% amino acid sequence homology.