The Role of Macronuclear DNA Sequences in the Permanent Rescue of a Non-Mendelian Mutation in Paramecium Tetraurelia
AUTOR(ES)
You, Y.
RESUMO
The Paramecium tetraurelia mutant called d48 has a complete copy of the A surface protein gene in its micronuclei, but lacks the A gene in the macronucleus. Previous experiments have shown that microinjection of a plasmid containing the entire A gene or a large portion of the gene into the macronucleus of d48 rescued the cell line after formation of a new macronucleus (autogamy). Here we show that several different regions of the A gene can rescue d48, but 100% of the activity cannot be localized to a single, defined region. Inversion of a sequence contained within an A gene plasmid had no measurable effect on rescue efficiency and co-injection of two different plasmids results in enhancement of rescue activity despite the non-contiguous form of the DNA sequences. Both these results suggest that no specific product (RNA or protein) with defined end points is made from the rescuing fragment. A unique restriction site was created in the A gene and used to demonstrate that the injected DNA does not serve as a direct template for the synthesis of the new macronuclear DNA. Models to explain the action of the injected DNA are discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1205912Documentos Relacionados
- Permanent Rescue of a Non-Mendelian Mutation of Paramecium by Microinjection of Specific DNA Sequences
- Non-Mendelian inheritance of macronuclear mutations is gene specific in Paramecium tetraurelia.
- Mendelian and non-mendelian mutations affecting surface antigen expression in Paramecium tetraurelia.
- Induced change in a non-mendelian determinant by transplantation of macronucleoplasm in Paramecium tetraurelia.
- Identification of DNA Segments Capable of Rescuing a Non-Mendelian Mutant in Paramecium