Fig 1: FUNDC2 in the porcine cell-free system.FUN14 domain-containing protein 2 was detected in ejaculated spermatozoa by Western blotting (A; predicted mass = 20.7 kDa). FUNDC2 was detected in the acrosome and equatorial segment of ejaculated spermatozoa (B) and the acrosome and mitochondrial sheath of capacitated spermatozoa (C). In primed spermatozoa, FUNDC2 was detected in the mitochondrial sheath and the remnants of the acrosome (D). After 4 hr of cell-free system exposure, FUNDC2 was detected throughout the tail of the treated spermatozoa (E), and after 24 hr of cell-free system exposure, FUNDC2 was detected in the mitochondrial sheath of treated spermatozoa (F). FUNDC2 was not detected localizing to the fertilizing sperm components in zygotes 15 hr post insemination (G). In contrast, a zona-bound spermatozoon at that same time point had FUNDC2 localized throughout the head and some tail localization as well (H). FUNDC2 was not detected localizing to the fertilizing sperm components in zygotes 25 hr post insemination (I), but a non-fertilizing spermatozoon bound to the oolemma at this same time point still had some FUNDC2 labeling in its tail and head, as shown by a fluorescent channel separated cutout (J).