We report the cloning of KIN17 cDNA, 1414 bp long with an ORF of 391 residues showing a zinc finger and nuclear localization signals. By recloning the cDNA into an appropriate vector, we produced kin17 protein in E. coli, purified it partially and shown that kin17 protein binds to double-stranded DNA. The KIN17 gene was localized by cytogenetic mapping in mouse chromosome 2, band A. Genomic sequences homologous to KIN17 cDNA were detected also in rat and human DNAs. KIN17 mRNA is highly expressed in rodent transformed AtT-20 neuroendocrine cells whereas it can be detected only in the total RNA of mouse embryos and various normal adult tissues by reverse transcription and PCR amplification. The mouse nuclear kin17 protein was identified by a local small structural similarity with E.coli recA protein. Kin17 and recA have only 39 amino acid residues in a region that might be involved in DNA-binding.