The highly conserved let-7 microRNA (miRNA) regulates developmental pathways across animal phyla. Mis-expression of let-7 causes lethality in C. elegans and has been associated with several human diseases. We show that timing of let-7 expression in developing worms is under complex transcriptional and post-transcriptional control. Expression of let-7 primary transcripts oscillates during each larval stage, but precursor and mature let-7 miRNAs do not accumulate until later in development after LIN-28 protein has diminished. We demonstrate that LIN-28 binds endogenous primary let-7 transcripts co-transcriptionally. We further show that LIN-28 binds endogenous primary let-7 transcripts in the nuclear compartment of human ES cells, suggesting that this LIN-28 activity is conserved across species. We conclude that co-transcriptional interaction of LIN-28 with let-7 primary transcripts blocks Drosha processing and, thus, precocious expression of mature let-7 during early development.
Pubmed ID: 21297634 RIS Download
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Software for automatic general image analysis. It provides fully automatic analysis of 1-D gels including lane creation, background subtraction, band detection, molecular weight calibration, quantity calibration, and normalization. Editing tools are provided for cropping, rotating, and filtering images.
View all literature mentionsCaenorhabditis elegans with name C. elegans wild type (ancestral). from WB.
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