Soggy-1, also known as DkkL1 (Dickkopf-like 1), is a secreted protein that is related to the Dickkopf family of Wnt antagonists. Mouse Soggy-1 is expressed at various sites in the embryo but in the adult is primarily found in the testes. Soggy-1 transcription is regulated by the spermatocyte specific factor, RFX2. During development, Soggy-1 is first detectable at the onset of sexual differentiation. It is localized to the acrosome in developing spermatocytes and mature spermatozoa.