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A cloned I-factor is fully functional in Drosophila melanogaster
M A Pritchard1, J M Dura, A Pélisson
1Department of Molecular Biology, University of Edinburgh, UK.
Molecular & General Genetics : MGG
|November 1, 1988
Summary
Researchers demonstrated that I-factors, a type of transposable element in Drosophila melanogaster, can cause hybrid dysgenesis. Introducing an I-factor into a reactive strain confirmed its ability to transpose and induce this phenomenon.
Area of Science:
- Molecular Biology
- Genetics
- Developmental Biology
Background:
- I-R hybrid dysgenesis in Drosophila melanogaster is controlled by transposable elements known as I-factors.
- I-factors are 5.4 kb elements structurally similar to mammalian LINE elements and other retroposons.
Purpose of the Study:
- To directly test the activity of an I-factor by introducing it into the genome of a reactive strain.
- To demonstrate that a specific retroposon is transposition proficient and to compare donor and transposed elements.
Main Methods:
- P-element mediated transformation was used to introduce an I-factor into the genome of a reactive Drosophila strain.
- Transposed copies of the I-factor were cloned and analyzed.
- Experiments involving plasmid injection and co-injection of marked I-factors were conducted to assess autonomous transposition.
Main Results:
- Introduction of an I-factor conferred the complete inducer phenotype on the reactive strain.
- Transformed males carrying the introduced I-factor stimulated dysgenesis when mated with reactive females.
- The introduced I-factor demonstrated transposition within the transformed lines, and cloned transposed copies were analyzed.
Conclusions:
- This study provides the first direct demonstration of a retroposon's transposition proficiency.
- A mechanism for I-factor transposition is proposed based on the experimental results and the elements' coding capacity.
- Autonomous transposition from injected plasmids or co-injected marked elements was not detected.