Abstract
GAL genes and other activated yeast genes remain tethered to the nuclear periphery even after transcriptional shutoff. To identify factors that affect this tethering, we designed a plasmid-based visual screen. Although many factors affected GAL tethering during transcription, fewer specifically affected posttranscriptional tethering. Tw o of these, Rrp6p and Lrp1p, are nuclear exosome components known to contribute to RNA retention near transcription sites (dot RNA). Moreover, these exosome mutations lead to a substantial posttranscriptional increase in polyadenylated
GAL1 3′ ends. This accompanies a loss of unadenylated (pA−)
GAL1 RNA and a loss of posttranscriptional gene-periphery tethering, as well as a decrease in dot RNA levels. This suggests that the exosome inhibits adenylation of some
GAL1 transcripts, which results in the accumulation of pA− RNA adjacent to the
GAL1 gene. We propose that this dot RNA, probably via RNP proteins, contributes to the physical tether linking the
GAL1 gene to the nuclear periphery.