Repeat-induced point mutation (RIP) has been used to generate new mutations in the previously uncharacterised gene for malate synthase in Neurospora crassa. Molecular clones carrying the am (NADP-glutamate dehydrogenase) gene and the malate synthase gene from either N. crassa or Aspergillus nidulans
Inactivation of the nopaline synthase gene by double transformation: reactivation by segregation of the induced DNA
β Scribed by Toru Fujiwara; Philip A. Lessard; Roger N. Beachy
- Publisher
- Springer
- Year
- 1993
- Tongue
- English
- Weight
- 847 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0721-7714
No coin nor oath required. For personal study only.
β¦ Synopsis
Tobacco plants were transformed with derivatives of a binary vector pMON505 and two kanamycin resistant lines that were nopaline positive were selected for second transformation. The plasmids used for the second transformation were derivatives of pMON850 which carries the nopaline synthase gene in addition to a gene for gentamicin resistance. Insertion of each transgene was confirmed by Southern hybridization. Surprisingly, we found that more than 50% of the doubly transformed tobacco plants were nopaline negative. Tobacco plants that were transformed only by the second vector exhibited nopaline accumulation. DNA methylation patterns at the HpaII site in the promoter region of the nopaline synthase gene did not correlate with the nopaline phenotype. In some plant lines, seedlings of the R1 generation which segregated out the second T-DNA insertion recovered the nop(+) phenotype. These results indicate that nopaline accumulation was inhibited by the presence of the second T-DNA.
π SIMILAR VOLUMES
Acquired resistance to antineoplastic agents is a frequent obstacle in tumor therapy. Malignant melanoma cells are particularly well known for their unresponsiveness to chemotherapy; only about 30% of tumors exhibit a transient clinical response to treatment. In our study, we investigated the molecu
## Abstract Although hydroquinone (HQ) is a rodent carcinogen, because of its lack of mutagenicity in standard bacterial mutagenicity assays it is generally considered a nongenotoxic carcinogen. 2,3,5β__Tris__β(glutathionβ__S__βyl)HQ (TGHQ) is a potent nephrotoxic metabolite of HQ that may play an
## Summary Two selectable marker genes harbouring the __bar__ coding region but differing in their promoters were compared in an __Arabidopsis thaliana__ transformation assay using __in planta__ infiltration with __Agrobacterium tumefaciens__. Surprisingly, in four __Arabidopsis__ ecotypes examined