Transcription of endogenous and exogenous R2 elements in the rRNA gene locus of Drosophila melanogaster.

ABSTRACT: R2 retrotransposons insert into the rRNA-encoding units (rDNA units) that form the nucleoli of insects. We have utilized an R2 integration system in Drosophila melanogaster to study transcription of foreign sequences integrated into the R2 target site of the 28S rRNA genes. The exogenous sequences were cotranscribed at dramatically different levels which closely paralleled the level of transcription of the endogenous R1 and R2 elements. Transcription levels were inversely correlated with the number of uninserted rDNA units, variation in this number having been brought about by the R2 integration system itself. Females with as few as 20 uninserted rDNA units per X chromosome had expression levels of endogenous and exogenous insertion sequences that were 2 orders of magnitude higher than lin

SUBMITTER: Eickbush DG 

PROVIDER: S-EPMC155226 | biostudies-literature | 2003 Jun

REPOSITORIES: biostudies-literature