A small noncoding RNA links ribosome recovery and translation control to dedifferentiation during salamander limb regeneration

Building a blastema from the stump is a key step of salamander limb regeneration. Stump-derived cells temporarily suspend their identity as they contribute to the blastema by a process generally referred to as dedifferentiation. Here, we provide evidence for a mechanism that involves an active inhibition of protein synthesis during blastema formation and growth. Relieving this inhibition results in a higher number of cycling cells and enhances the pace of limb regeneration. By small RNA profiling and fate mapping of skeletal muscle progeny as a cellular model for dedifferentiation, we find that the downregulation of miR-10b-5p is critical for rebooting the translation machinery. miR-10b-5p targets ribosomal mRNAs, and its artificial upregulation causes decreased blastema cell proliferation, reduction in transcripts that encode ribosomal subunits, diminished nascent protein synthesis, and retardation of limb regeneration. Taken together, our data identify a link between miRNA regulation, ribosome biogenesis, and protein synthesis during newt limb regeneration. [Display omitted] •MKNK2 is selectively expressed in blastema cells, expressing a low number of genes•MKNK2 expression is compartmentalized, and its inhibition enhances limb regeneration•Transient downregulation of miR-10b occurs during blastema growth•Interference with miR-10b downregulation inhibits limb regeneration Subramanian, Elewa, Brito et al. show that active inhibition and rebooting of protein synthesis occur during blastema formation and growth. This study identifies links among miRNA regulation, ribosome biogenesis, and protein biosynthesis during newt limb regeneration.