Wdr4 regulates ribosome biogenesis and intestinal homeostasis via let-7
Year: 2026
Type: article
Abstract: Proper regulation of ribosome biogenesis is essential for stem cell function and tissue homeostasis, yet its upstream control in adult intestinal stem cells (ISCs) remains unclear. Here, we identify the WD repeat protein Wdr4 as a key regulator of ISC homeostasis in the Drosophila midgut. Wdr4 cooperates with the methyltransferase Mettl1 to catalyze N⁷-methylguanosine (m⁷G) modification of let-7 miRNA. Wdr4 or Mettl1 depletion disrupts this modification, reducing let-7 levels and aberrantly activating TOR-JNK-dMyc signaling. This drives elevated ribosome biogenesis, ISC overproliferation, misdifferentiation, and intestinal dysplasia. Overexpression of let-7, inhibition of TOR, or suppression of JNK rescues these defects. Importantly, expression of human WDR4 and METTL1, but not catalytic-dead METTL1 mutant, restores ISC homeostasis in Wdr4- and Mettl1-depleted flies, establishing a conserved Wdr4/Mettl1-let-7-TOR-JNK axis that links miRNA modification to translational control and tissue integrity. Together, our findings uncover a previously unrecognized function of miRNA m⁷G methylation in regulating ribosome biogenesis and maintaining intestinal homeostasis.
Source: EMBO Reports
Institutions: National Chung Hsing University, Institute of Cellular and Organismic Biology, Academia Sinica, Academia Sinica, National Taipei University, The University of Texas Health Science Center at Houston, National Chiayi University, National Health Research Institutes, Taipei Medical University, Institute of Biomedical Sciences, Academia Sinica, The University of Texas MD Anderson Cancer Center
Language: English
Topic: RNA modifications and cancer
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $7,990
Awards: G3409274628, G6321960221
OpenAlex ID: W7128447231