Use of Red-Green transgenic mice to correlate antibody staining of MFN2 and MNS1 with mitochondria. Panels (A-D) are unstained, fixed germ cells. RFP is expressed in the mitochondria (B), and GFP is expressed in proacrosomal granules or the developing acrosomes (C). Immunofluorescence of spermatogenic cells with anti-MFN2 (E-H) or anti-MNS1 (I-L) was performed. MFN2 localized to the germ cell mitochondria (G). MNS1 was seen in a speckle pattern throughout the sperm cytoplasm (K). Panels (A, E, I) are Nomarski differential interference contrast micrographs. Panels (B, F, J) display RFP in the mitochondria. Panels (D, H, L) are merged images. The second antibody is labeled with Alexa Fluor 488 (green) and are indicated in panels (C, G, K). A 5 μm bar is indicated on all images.