DNA polymerase mu and uses thereof

Abstract

A novel DNA polymerase (Pol μ) and nucleic acid encoding it is provided from both human and murine sources. Human Pol μ is 494 amino acids long and has about 40 % sequence identity with TdTs from different origins. This novel DNA polymerase has terminal transferase activity, but it is strongly stimulated by the presence of a template strand. In the presence of Mn2+ or Mg2+ ions, Pol μ catalyses a random insertion of deoxynucleotides in front of various template bases. In the presence of Mg2+ ions, Pol μ has a very reduced base discrimination, mainly producing the insertion of A and T in front of a template G. This new enzyme is, therefore, the DNA-dependent DNA polymerase with the lowest value of insertion fidelity, a property that enables Pol μ to be an useful tool in processes oriented to modify the DNA and in the diagnosis of cancer and in particular B cell lymphomas.