A growth factor-inducible nuclear protein with a novel cysteine/histidine repetitive sequence

Growth factors rapidly induce transcription of a set of genes that encode regulatory proteins, many of which have been identified by cDNA cloning. Here we report the analysis of a cDNA corresponding to a gene induced in mouse 3T3 cells by growth factors and a variety of other extracellular signaling agents. The cDNA encodes a proline-, serine-, and glycine-rich nuclear protein designated Nup475 of 319 amino acids that contains two tandemly repeated cysteine- and histidine-containing sequences (CX₈CX₅CX₃R) suggestive of a novel heavy metal-binding domain. Nup475 produced in Escherichia coli binds zinc. Its mRNA is present in a number of mouse tissues and cell lines, being especially abundant in intestine, thymus, and regenerating liver and in a macrophage cell line stimulated by γ-interferon. We hypothesize that Nup475 is a regulatory protein with a novel zinc finger structure.