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R Nutter

Publications and source records attributed to R Nutter.

8 recordsLinked to original sources
PubMed1987

Factors affecting the level of kanamycin resistance in transformed sunflower cells.

A 230 base pair DNA segment containing the sequences 5' to the 700 to 750 nucleotide (nt) transcript 7' (ORF 3; RF Barker, KB Idler, DV Thompson, JD Kemp 1983 Plant Mol Biol 2: 335-350) of the octopine tumor inducing plasmid pTiA6 has been isolated. This region has (a) 180 base pairs of DNA upstream of the TATA box, (b) the start of RNA synthesis, and (c) the entire 5' untranslated region of the gene. We have fused this presumed promoter fragment to the neomycin phosphotransferase II (NPTII) gene from Tn5 in a plant expression cassette. After recombination into a tumor inducing plasmid delivery plasmid, this cassette confers selectable kanamycin resistance to transformed sunflower cells. Removal of the out-of-frame ATG in the 5' leader sequence of the NPTII gene by two different modifications increased both the levels of NPTII enzyme activity and the ID(50) for kanamycin in the tumor cells. The promoter region of the transcript 7 gene gives levels of kanamycin resistance equivalent to the nopaline synthase promoter and octopine synthase promoter when used in the same constructions and assayed in the same tissues.

Journal Article↗
PubMed1980

Integration and organization of Ti plasmid sequences in crown gall tumors.

The Ti plasmid sequences (T DNA) maintained in four unorganized crown gall tumor lines were defined by using restriction endonucleases and molecular hybridization techniques. Each tumor line contains a "core" T DNA which is apparently responsible for maintaining the transformed state; the core T DNA is colinear with the Ti plasmid and contains the Ti plasmid sequences referred to as the "common DNA"--sequences found in all Ti plasmids studied to date. A given Ti plasmid does not always give rise to the same T DNA complement. The data suggest that the majority if not all of the T DNA is integrated into plant DNA, that preferred regions of the Ti plasmid serve as the points of attachment to plant DNA and that the T DNA can be linked to more than one site in the plant genome.

Base Sequence↗
PubMed1980

Recombination between higher plant DNA and the Ti plasmid of Agrobacterium tumefaciens.

The Ti plasmid sequences (T-DNA) from the octopine-producing crown gall tumor A6S/2 were isolated by molecular cloning, using the bacteriophage lambda vector Charon 4A. Analysis of the cloned DNA segments indicates that the Ti plasmid sequences are covalently joined to plant nuclear DNA. These data demonstrate that genetic recombination between a eukaryote and a prokaryote can occur as a natural phenomenon.

Journal Article↗