The FOXI1 antibody is a tool used to detect Forkhead box I1 (FOXI1), a transcription factor belonging to the forkhead box (FOX) protein family. FOXI1 plays critical roles in regulating gene expression involved in ion transport, fluid homeostasis, and cellular differentiation. It is specifically expressed in tissues such as the inner ear (cochlea and vestibular system), kidney (intercalated cells), and epididymis, where it regulates the function of ion channels, including those critical for acid-base balance (e.g., V-ATPase). Antibodies targeting FOXI1 are widely used in research to study developmental biology, renal physiology, and auditory function. They enable visualization and quantification of FOXI1 protein expression via techniques like immunohistochemistry, Western blotting, and immunofluorescence. FOXI1 antibodies have also been instrumental in exploring pathologies linked to its dysfunction, such as distal renal tubular acidosis and hearing loss. Validated antibodies are typically raised in rabbits or mice, with specificity confirmed through knockout controls or siRNA-mediated silencing. Recent studies highlight FOXI1's role in cell-type specification in the kidney and its interaction with other transcription factors (e.g., POU3F4) in auditory development. Its conserved structure (a forkhead DNA-binding domain) and tissue-specific expression make FOXI1 a key target for understanding epithelial cell biology and related disorders.