We are interested in the genetic control of telomere structure and identity, and have focused on the model organism, Drosophila melanogaster. Mutations in this organism are known that drastically increase or decrease the frequency of additions of telomere-specific retrotransposon to a chromosome end, suggesting that this process is under genetic control. We have identified one gene, Telomere elongation (Tel), which has mutations that increase the frequencies of both terminal gene conversion and targeted transposition, and are using positional information to clone the gene. The Tel gene maps to the middle of right arm of chromosome 3 to a region of approximately 77 kb, which includes nine protein coding genes, a miRNA gene and a gene for a snoRNA. Sequencing the coding regions of these genes did not identify a high probability candidate gene. The observations that the Tel mutations are genetically dominant and that deletions for the region do not have a telomere elongation phenotype suggest that the mutations are gain-of-function mutations and may be in controlling regions. Deep sequencing the mutant and comparison with several wild type strains with short telomeres identified two short deletions in intergenic and intronic regions that may be of interest. This analysis also identified three new variant strains with exceptionally long telomeres. Chromatin structure may regulate telomere length by controlling transcription of the telomeric retrotransposons and by controlling accessibility of the retroelements to the chromosome end. We have initiated a project to mark a HeT-A transposable element with a transcribed gene in order to follow the transposon as it moves from one chromosome end to another. A HeT-A element has been constructed inside a EPgy2 transposon and inserted into the genome of a fly to assay transposition in vivo. If the assay works, it will allow us to investigate what genetic and environmental factors influence the rate of movement, either by classical retrotransposition or by telomeric gene conversion.
| Antao, Jose M; Mason, James M; Dejardin, Jerome et al. (2012) Protein landscape at Drosophila melanogaster telomere-associated sequence repeats. Mol Cell Biol 32:2170-82 |
| Takacs, Sandor; Biessmann, Harald; Reddy, Hemakumar M et al. (2012) Protein interactions on telomeric retrotransposons in Drosophila. Int J Biol Sci 8:1055-61 |
| Dronamraju, Raghuvar; Mason, James M (2011) MU2 and HP1a regulate the recognition of double strand breaks in Drosophila melanogaster. PLoS One 6:e25439 |
| Capkova Frydrychova, R; Biessmann, H; Mason, J M (2008) Regulation of telomere length in Drosophila. Cytogenet Genome Res 122:356-64 |
