Suppressors of transcriptional transgenic silencing in Chlamydomonas are sensitive to DNA-damaging agents and reactivate transposable elements.

ABSTRACT: In the unicellular green alga Chlamydomonas reinhardtii, the epigenetic silencing of transgenes occurs, as in land plants, at both the transcriptional and posttranscriptional levels. In the case of single-copy transgenes, transcriptional silencing takes place without detectable cytosine methylation of the introduced DNA. We have isolated two mutant strains, Mut-9 and Mut-11, that reactivate expression of a transcriptionally silenced single-copy transgene. These suppressors are deficient in the repression of a DNA transposon and a retrotransposon-like element. In addition, the mutants show enhanced sensitivity to DNA-damaging agents, particularly radiomimetic chemicals inducing DNA double-strand breaks. All of these phenotypes are much more prominent in a double mutant strain. These observa

SUBMITTER: Jeong Br BR 

PROVIDER: S-EPMC117432 | biostudies-literature | 2002 Jan

REPOSITORIES: biostudies-literature