SPE-9 is a cell surface protein. Non-permeabilized spermatids incubated with anti-SPE-9-EX and 1CB4 (A-C) or anti-SPE-9-C and 1CB4 (D-F). A and D show Nomarski DIC images. B and E show the anti-SPE-9 staining pattern on these cells. C and F show the lack of 1CB4 staining. DAPI staining of nuclei is blue. Dashed lines in C, E and F indicate the positions of the cells. Bar in D is 5 μm and applies to all panels.