By screening with labeled Alu DNA, a clone was isolated from cDNA expression library, which appeared identical in sequence to the well-known Ca-phospholipid-binding protein annexin II. To evidence the DNA-binding activity of recombinant annexin II and its presence in the cell nucleus, we have expressed full-lenght mouse annexin II cDNA in bacteria with pGEMEX vector. The expressed protein was studied with electrophoretic mobility shift assay and for its reaction with polyclonal antibody to chromatin-associated ribonucleoprotein (α-RNP), which is one of the major acid-dissolvent components of the nucleus. The obtained results confirm the DNA-binding activity of recombinant annexin II. Annexin II reacts with polyclonal antibody to rat α-RNP. So, annexin II is a major nuclear DNA-binding protein in mammalian cells.