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Mol Cell Biol. 2000 Oct;20(20):7634-42.

Attachment of HeT-A sequences to chromosomal termini in Drosophila melanogaster may occur by different mechanisms.

Author information

1
Department of Control of Genetic Processes, Institute of Gene Biology, Russian Academy of Sciences, 117334 Moscow, Russia.

Abstract

Drosophila telomeres contain arrays of the retrotransposonlike elements HeT-A and TART. Their transposition to broken chromosomal termini has been implicated in chromosome healing and telomere elongation. The HeT-A element is attached by its 3' end, which contains the promoter. To monitor the behavior of HeT-A elements, we used the yellow gene with terminal deficiencies consisting of breaks in the yellow promoter region that result in the y-null phenotype. Attachment of the HeT-A element provides the promoterless yellow gene with a promoter that activates yellow expression in bristles. The frequency of HeT-A transpositions to the yellow terminal deficiency depends on the genotype of the line and varies from 2 x 10(-3) to less than 2 x 10(-5). Loss of the attached HeT-A due to incomplete replication at the telomere leads to inactivation of yellow expression, which is restored by attachment of a new HeT-A element upstream of yellow. New HeT-A additions occur at a frequency of about 1.2 x 10(-3). Short DNA attachments are generated by gene conversion using the homologous telomeric sequences as templates. Longer DNA attachments are generated either by conventional transposition of an HeT-A element to the chromosomal terminus or by recombination between the 3' terminus of telomeric HeT-A elements and the receding end of HeT-A attached to the yellow gene.

PMID:
11003659
PMCID:
PMC86327
DOI:
10.1128/mcb.20.20.7634-7642.2000
[Indexed for MEDLINE]
Free PMC Article

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