Kr ppel-like factors (KLFs) comprise a family of evolutionarily conserved zinc finger-containing transcription factors with diverse regulatory functions in cell growth, proliferation, differentiation and embryogenesis. Individual members of the Sp1-like/KLF family can function either as activators or repressors, depending on which promoter they bind and which co-regulators they interact with. KLF17 (Kr ppel-like factor 17), whose alternative names include ZNF393 (zinc finger protein 393) or zfp393, is a 389 amino acid nuclear protein belonging to the Sp1 C2H2-type zinc-finger protein family. Expressed in testis and ovary, KLF17 may function as a germ cell-specific transcription factor involved in oocyte development and spermatid differentiation. Containing three C2H2-type zinc fingers which bind G/C-rich sites, KLF17 activates transcription from CACCC-box elements.