coh-2 was expressed primarily in germline cells as seen by immunofluorescence. Its product was present as dots, mainly at the periphery but also inside nuclei of the mitotic zone. In later stages, COH-2 assumed an exclusively peripheral distribution. In pachytene nuclei, 10 (10.1 1.5 [n = 25 nuclei]) distinct spots were counted but by diplotene and later COH-2 was not detectable. COH-2 was present in the nuclei of embryos but was not associated with condensed mitotic chromosomes.