TRANSPORT OF DNA INTO THE NUCLEI OF XENOPUS OOCYTES BY A MODIFIED VIRE2 PROTEIN OF AGROBACTERIUM

We used Agrobacterium T-DNA nuclear transport to examine the specifici ty of nuclear targeting between plants and animals and the nuclear imp ort of DNA by a specialized transport protein. Two karyophilic Agrobac terium virulence (Vir) proteins, VirD2 and VirE2, which presumably ass ociate with the transported T-DNA and function in many plant species, were microinjected into Drosophila embryos and Xenopus oocytes. In bot h animal systems, VirD2 localized to the cell nuclei and VirE2 remaine d exclusively cytoplasmic, suggesting that VirE2 nuclear localization signals may be plant specific. Repositioning one amino acid residue wi thin VirE2 nuclear localization signals enabled them to function in an imal cells. The modified VirE2 protein bound DNA and actively transpor ted it into the nuclei of Xenopus oocytes. These observations suggest a functional difference in nuclear import between animals and plants a nd show that DNA can be transported into the cell nucleus via a protei n-specific pathway.