title: T-DNA organization in homogeneous and heterogeneous octopine-type crown gall tissues of Nicotiana tabacum.
abstract: Octopine-type tumor tissue was obtained both by infection of plants or isolated protoplasts with Agrobacterium tumefaciens and by somatic hybridization of normal and crown gall tobacco cells. Analysis of T-DNA by Southern blotting of clones and uncloned tissue reveals that, whereas tumors induced on plants are heterogeneous mixtures of cells differing in T-DNA organization, each tissue derived from transformed protoplasts or from somatic hybridization is homogeneous. Detailed analysis of T-DNA organization showed that TL- or "core" T-DNA was always present at one or two copies per diploid genome. However, sometimes it was present in a modified form, either deleted, extended, tandemly duplicated or probably methylated. TR-DNA was not detected. The observed variation in the organization of T-DNA in octopine crown gall tissue did not appear to be a characteristic of the way the tissue was derived.
mesh_terms: D001120:Arginine / Q000031:analogs & derivatives / Q000032:analysis; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis*; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000032:analysis*; D008745:Methylation; D009693:Nucleic Acid Hybridization; D010941:Plant Tumors / Q000032:analysis*; D010947:Plants, Toxic; D011523:Protoplasts / Q000382:microbiology; D012231:Rhizobium / Q000235:genetics*; D014026:Nicotiana
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; C005394:octopine; D004247:DNA; D001120:Arginine; D004262:DNA Restriction Enzymes