May be involved in the final steps of mitochondrial differentiation within the flagellum. Predominantly nuclear. Some fraction is associated with mitochondria. Expression limited to post-meiotic male germ cells. Expressed in elongated spermatids during individualization and in finally elongated nuclei of spermatids. After completion of nuclear shaping it is no longer expressed in the sperm heads with the onset of individualization. Expressed post-meiotically.