Our previous study documented expression of a male-transmitted cytochrome c oxidase subunit II protein (MCOX2), with a C-terminus extension (MCOX2e), in unionoidean bivalve testes and sperm mitochondria. Here, we present evidence demonstrating that MCOX2 is seasonally expressed in testis, with a peak shortly before fertilization that is independent of sperm density. MCOX2 is localized to the inner and outer sperm mitochondrial membranes and the MCOX2 antibody’s epitope is conserved across >65 million years of evolution. We also demonstrate the presence of male-transmitted mtDNA and season-specific MCOX2 spatial variation in ovaries. We hypothesize that MCOX2 plays a role in reproduction through gamete maturation, fertilization and/or embryogenesis.
Walker, J. M.,
(2007). Reproductive Function for a C-terminus Extended, Male-Transmitted Cytochrome c Oxidase Subunit II Protein Expressed In Both Spermatozoa and Eggs. FEBS Letters, 581(27), 5213-5219.
Available at: https://aquila.usm.edu/fac_pubs/8487