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Updated: Aug 17, 2026
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Quantitative Comparison of cis-Regulatory Element (CRE) Activities in Transgenic Drosophila melanogaster
Published on: December 19, 2011
A rapid decrease in number of the complete ninja element and concomitant increase of the defective element in a
Keiji Ogura1, Takashi Ohsako, Masa-Toshi Yamamoto
1Drosophila Genetic Resource Center, Kyoto Institute of Technology, Saga Ippongi-cho, Ukyo-ku, Kyoto, 616-8354, Japan.
Genetica
|July 14, 2005
Summary
The ninja retrotransposon, found in Drosophila, shows varying copy numbers across mutant strains. A specific deletion in the w(mky3) strain suggests reduced integration of full-length ninja elements, possibly due to ectopic splicing.
Area of Science:
- Genetics
- Molecular Biology
- Evolutionary Biology
Background:
- The ninja element is a long terminal repeat (LTR) retrotransposon identified in Drosophila simulans.
- Its copy number varies significantly across different mutant strains derived from the white-milky (w(mky)) strain.
Purpose of the Study:
- To investigate the copy number and structural integrity of ninja elements in various Drosophila simulans sublines.
- To understand the mechanisms behind the observed changes in ninja element abundance, particularly in the w(mky3) strain.
Main Methods:
- Cloning and structural analysis of ninja elements from different Drosophila sublines (w(mky), w(cho), w(psm1), w(mky3)).
- Comparative analysis of full-length versus defective ninja element structures and their copy numbers.
Main Results:
- Ninja elements are present in high copy numbers in w(cho) and w(psm1) sublines, but in low numbers in w(mky3) and wild-type strains.
- Most cloned ninja elements from w(cho) were full-length, whereas a significant proportion from w(mky3) were defective.
- Three defective ninja elements from w(mky3) shared an identical 81-bp deletion in both 5' and 3' LTRs, resembling Drosophila consensus splicing sites.
Conclusions:
- The decrease in ninja element numbers in the w(mky3) strain is likely due to a reduced integration rate of full-length elements, not an increased loss rate.
- Ectopic splicing is hypothesized to be the mechanism responsible for generating the specific deletions observed in defective ninja elements from the w(mky3) strain.
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