BTEB/KLF9(basic transcription element-binding protein/Krüppel-like transcription factor 9), a member of Krüppel-like transcriptional factors, is a zinc finger protein involved in regulating gene transcription in eukaryocyte. Substantial expression of BTEB mRNA is detected in a variety of cell lines and tissues, but BTEB protein is not consistent with its mRNA. BTEB regulates transcription through its carboxyl-terminal C2H2 zinc finger motif binding to GC or GT/CACC box, a sort of cis-acting elements, which is wildly distributed in promoters, enhancers and control regions of many genes. BTEB/KLF9 functions as a transcription factor by direct or functional interaction with other transcription factors and/or coactivators/corepressors, and plays a role in reproductive system, cell proliferation, differentiation, and cell cycle regula-tion.