Identification of the Telomere elongation mutation in Drosophila
- Published
- Accepted
- Subject Areas
- Genetics
- Keywords
- Drosophila melanogaster, telomere, transposon induced recombination, next generation sequencing
- Copyright
- © 2018 Reddy et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2018. Identification of the Telomere elongation mutation in Drosophila. PeerJ Preprints 6:e26708v1 https://doi.org/10.7287/peerj.preprints.26708v1
Abstract
Background. Telomeres in Drosophila melanogaster are similar to those of other eukaryotes in terms of their function, although they are formed by non-LTR retrotransposons instead of telomerase-based short repeats. The length of the telomeres in Drosophila depends on the number of copies of these transposable elements. A dominant mutation, Tel1, causes a several-fold elongation of telomeres.
Methods. In this study we identified the Tel1 mutation by a combination of transposon-induced, site-specific recombination and next generation sequencing.
Results. Recombination located Tel1 to a 15 kb region in 92A. Comparison of the DNA sequence in this region with the Drosophila Genetic Reference Panel of wild type genomic sequences delimited Tel1 to a 3 bp deletion inside intron 8 of Ino80.
Discussion. The mapped Tel1 mutation (3-bp deletion found in Ino80) did not appear to affect the quantity or length of the Ino80 transcript. Tel1 causes a significant reduction in transcripts of CG18493, a gene nested in an intron 8 of Ino80, which is expressed in ovaries and expected to encode a serine-type peptidase.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Figure S1 Telomere length in recombinants from transposons used for Tel1 mapping
Change in relative HeT-A copy number in different recombinant stocks from generation 0 to 12. Recombinants carrying ca are shown in purple; those bearing st in red.
FlyBase browser map of the 77kb Tel1 region with indels and Minos insertion sites
Genome browser map for the 77 kb region between 05151 and d10097 (red vertical lines). Blue arrows show the location of two candidate indels (deletion C and deletion TGT). Two transposon insertions, MI03112 and MI02316, which lie between the two indels, were used for further mapping the Tel1 mutation. Red arrow indicates the MB09416 transposon insertion site. Flies carrying this insertion have long telomeres.
Sequence conservation among insect species at Tel1 and MB09416 insertion loci
UCSC Genome Browser maps showing conservation in the immediate vicinity of the Tel1 mutation (deletion TGT) and the MB09416 insertion. The sequence around the Tel1 mutation shows good conservation among different Drosophila and insect species, whereas the sequence surrounding the MB09416 insertion site is not well conserved.
PCR with flanking primers to large indels found in Tel genome
PCR products spanning two large indels 145 bp (3R: 15,157,140 – 284) and 85 bp (3R:15,170,445-524) from Tel and y w. These indels were identified in the Tel1 genome by manual scanning the CLC Genomics assembly. PCR product of 145 bp deletion shows a band size difference of ~40 bp, whereas 85 bp deletion shows expected band size variation.