An intron-based timer for circadian rhythms.

ABSTRACT: Circadian clocks regulate daily rhythms in all eukaryotes through ~24-hour transcriptional-translational feedback loops driven by clock proteins. However, the molecular mechanisms that set the 24-hour period remain poorly defined. Here, using single-molecule imaging and nascent RNA sequencing, we uncover an unexpected RNA-based molecular timer: a single intron in the Drosophila timeless (tim) gene that regulates circadian period length by controlling mRNA localization. Strikingly, we find that ~50% of tim mRNAs are localized to the nucleus due to inefficient post-transcriptional splicing of a single intron (which we named intron P), in contrast to other core clock transcripts that localize predominantly to the cytoplasm. CRISPR-mediated removal of intron P aboli

SUBMITTER: Yuan Y 

PROVIDER: S-EPMC12636426 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature