Molecular basis of Agrobacterium-mediated gene transfer into mammalian cells

Abstract

A novel system for detection of gene transfer between A. tumefaciens and mammalian cells was established. Using this system, Agrobacterium was found to be able to deliver DNA located on its plasmid and chromosome into human cells. Agrobacterium is actively involved in this process; such a kind of DNA transfer might occur widely between bacteria and mammalian cells. The frequency of such a gene transfer was approximately 10-4-10-5 transformants per recipient. Our data showed that this DNA transfer is dependent upon Agrobacterium and independent of its virulence genes. The polymerization of actin played an important role in Agrobacterium internalization and subsequent gene transfer into mammalian cells. In addition, an Agrobacterium sensor protein ChvG was found to be important for the gene transfer into both plant and mammalian cells. The data suggested that ChvG was involved in the regulation of acid-inducible genes and might function as a global sensor protein that can directly or indirectly sense extracellular acidity.