FIG. 4.
The Spag5 null mutation abolishes testicular Spag5 protein synthesis. The synthesis of Spag5 protein in testicular germ cells was analyzed and compared in Spag5+/− heterozygotic mice (lanes 1, 3, 5, and 7 [indicated by “+”) and Spag5−/− mice (lanes 2, 4, 6, and 8 [indicated by “−”). Isolated germ cells were incubated in the presence of [35S]methionine, and radiolabeled de novo-synthesized proteins were characterized directly (lanes 1 and 2) or after immunoprecipitation with anti-Spag5 antibodies (lanes 3 and 4), preimmune antiserum (lanes 5 and 6), or anti-Odf2 antibodies (lanes 7 and 8). Immunoprecipitated proteins and whole lysates were analyzed by SDS-PAGE and autoradiography. Lanes 1 and 2 show the total labeled protein pattern. Spag5 is indicated, as are the Odf2 peptides. Note the absence of Spag5 protein in the Spag5−/− mice.