A team at Duke University has developed an approach to deliver machinery aimed at regenerating tissue into a mouse model of heart attack, as they report Tuesday in Cell Stem Cell. They isolated tissue-regeneration enhancer elements, dubbed TREES, from zebrafish, which control repair-related gene activity at injury sites. By combining TREES with CRISPR-based epigenome editing tools, delivered using an adeno-associated virus, the researchers examined whether these elements could also be effective in adult mammals. In the mice, they found, this approach could boost tissue regeneration and improve heart function. "Here, we find that even in situations of limited regenerative capacity, the transcriptional machinery of small and large adult mammals can recognize and be instructed by TREE sequences from zebrafish, present in transgenes or viral vectors," the researchers write. They add that their work lays the "foundation for new gene-therapy approaches to improve tissue repair in disease settings."