A unique clone from a human pancreatic cDNA library was isolated and sequenced. Examination of the deduced polypeptide sequence of the clone showed a new form of cysteine-rich domain that included a region with the form of a Cys4 zinc-finger-like metal binding site followed by a complex Cys-His region. Searches of the Swiss-Protein data bank found a similar 48-residue domain in fifteen open reading frames deduced from A. thaliana, C. elegans, S. cerevisiae and S. pombe genomic sequences. The high degree of conservation of this domain (13 absolutely conserved and 17 highly conserved positions) suggests that it has an important function in the cell, possibly related to protein-protein or protein-DNA interactions. The gene recognized by the clone is is localized to human chromosome 16, and is conserved in vertebrates. The 2 Kb message is expressed in various human fetal and adult tissues. An antibody made to a peptide sequence of the deduced protein showed reactivity in immunoblots of monkey lung and retinal subcellular fractions and immunohistochemically in late fetal mouse tissues and a limited number of adult mouse tissues, including pancreatic islets, Leydig cells of the testis, and the plexiform layers of the retina.