Proteins encoded by Agrobacterium tumefaciens Ti plasmid DNA (T-DNA) in crown gall tumors

Abstract

To detect proteins that may be produced in crown gall tumors as a result of expression of incorporated A. tumefaciens Ti plasmid DNA (T-DNA), mRNA complementary to T-DNA was isolated and it was translated in a protein-synthesizing system derived from wheat germ. mRNA prepare from cultured E1 tumor from Nicotiana tabacum hybridized with HindIII fragment 1 sequences of T-DNA immobilized n cellulose nitrate filters. Two proteins of 30,000 and 16,500 MW were produced when this selected RNA was released and translated. Other tumor lines from N. tabacum were investigated, and a protein of slightly less than 30,000 MW was encoded by HindIII fragment 1 sequences of 15955/01 tumor. No products were observed for 15955/1 tumor line, which differs from El/B6-806 and 15955/01 in that it does not produce octopine. mRNA species of each of the tumor lines hybridized to Bst I fragment 8 sequences of T-DNA and produced a common protein of 15,000 MW. Because this protein is derived from the region of the T-DNA that is conserved in octopine- and nopaline-type crown gall tumors, it may play a role in oncogenicity.