A Tat-grafted anti-nucleic acid antibody acquires nuclear-localization property and a preference for TAR RNA

The 3D8 single chain variable fragment (3D8 scFv) is an anti-nucleic acid antibody that can hydrolyze nucleic acids and enter the cytosol of cells without reaching the nucleus. The Tat peptide, derived from the basic region of the HIV-1 Tat protein, translocates to cell nuclei and has TAR RNA binding activity. In this study, we generated a Tat-grafted antibody (H3Tat-3D8) by replacing complementarity-determining region 3 (CDR3) within the VH domain of the 3D8 scFv with a Tat48–60 peptide (GRKKRRQRRRPPQ). H3Tat-3D8 retained the DNA-binding and DNA-hydrolyzing activity of the scFv, and translocated to the nuclei of HeLa cells and preferentially recognized TAR RNA. Thus, the properties associated with the Tat peptide were transferred to the antibody via Tat-grafting without loss of the intrinsic DNA-binding and hydrolyzing activities of the 3D8 scFv antibody.

► We generate “H3Tat-3D8” by grafting Tat48–60 peptide to VH CDR of 3D8 scFv antibody. ► H3Tat-3D8 antibody retains nucleic acid binding and hydrolyzing activities. ► H3Tat-3D8 acquires a preference for TAR RNA structure. ► Properties of Tat48–60 is transferred to an antibody via Tat-grafting into a CDR.