Transposable elements (TEs) encode regulatory elements that impact gene expression in multiple species, yet a comprehensive analysis of zebrafish TEs in the context of gene regulation is lacking. Here, we systematically investigate the epigenomic and transcriptomic landscape of TEs across 11 adult zebrafish tissues using multidimensional sequencing data. We find that TEs contribute substantially to a diverse array of regulatory elements in the zebrafish genome and that 37% of TEs are positioned in active regulatory states in adult zebrafish tissues. We identify TE subfamilies enriched in highly specific regulatory elements among different tissues. We use transcript assembly to discover TE-derived transcriptional units expressed across tissues. Finally, we show that novel TE-derived promoters can initiate tissue-specific transcription of alternate gene isoforms. This work provides a comprehensive profile of TE activity across normal zebrafish tissues, shedding light on mechanisms underlying the regulation of gene expression in this widely used model organism.

: Polycystic ovary syndrome (PCOS) is a frequent endocrine and metabolic imbalance that typically occurs in women of reproductive age. Its molecular pathophysiology is yet unknown, especially the ovarian cellular metabolic inefficiency that causes the transcriptional dysregulation of key genes linked to PCOS. Here, we discovered that one transcriptional-like regulator that causes PCOS is nuclear pyruvate kinase M2 (nPKM2). Using multiomics techniques, we show that enhanced lactylation of histone 3 on lysine residues 9 and 18 is linked to nPKM2 binding to the genome, changing the three-dimensional architecture of the genome. Genomic compartment switching, topologically associated domain fusion, and novel enhancer–promoter interactions subsequently enhance the expression of PCOS-related genes, including CYP17A1 and CYP11A1 . In mice, ectopic expression of Pkm2 in female GCs consistently presented PCOS-like traits, such as interrupted estrous cycles, hyperandrogenism, and so on. Importantly, whole-organ tracing imaging directly unfolded the number of small follicles, which increased highly in Pkm2 -tdtomato transgene mice compared with control. Furthermore, pharmacological inhibition of the nuclear accumulation of PKM2 mitigated PCOS-like symptoms in mice and restored a wild-type-like transcriptome. This study demonstrates the important function of PKM2-mediated histone lactylation in regulating the three-dimensional chromatin architecture and highlights PKM2 as a potential therapeutic target for PCOS treatment.

Genetic mutations cause hereditary deafness, in which mutations in the POU4 transcription factor 3 gene (POU4F3) lead to autosomal dominant non-syndromic deafness 15 (DFNA15), for which no effective clinical treatment currently exists. Gene editing holds promise for precisely repairing mutated nucleotides, thus offering a potential cure for hereditary hearing loss. Here, we establish a Pou4f3^WT/Q113* mutant mouse model mimicking DFNA15. We develop and screen adenine base editors (ABEs) targeting the Pou4f3^Q113* allele by fusing diverse adenine deaminases to Cas9 we discovered before. SchABE8e accomplishes highly precise and efficient editing (up to 48.5%) at sgRNA3 in vitro. Neonatal Pou4f3^WT/Q113* mice are treated via synthetic AAV (Anc80L65)-delivered SchABE8e-sgRNA3, resulting in near-complete hearing recovery, with the effect persisting for at least four months. Biosafety analyses further support the feasibility of base editing, providing a therapeutic strategy for DFNA15.

Background: Contemporary cochlear implants (CIs) face unresolved dual challenges: biomechanical-electrochemical mismatch at the electrode-tissue interface and progressive spiral ganglion neuron (SGN) degeneration, severely limiting long-term auditory restoration. Integrating regenerative medicine with bioelectronic engineering offers promise to overcome these bottlenecks.