iCLIP-seq identifies direct binding of PETISCO complex to replication-dependent histone mRNAs in Caenorhabditis elegans embryos

This study uses individual-nucleotide resolution UV crosslinking and immunoprecipitation (iCLIP) to map the direct RNA-binding sites of the PETISCO complex in Caenorhabditis elegans embryos. When bound to TOST-1, PETISCO stabilizes replication-dependent histone mRNAs during oogenesis to ensure adequate maternal histone supply for early embryogenesis. To identify the direct RNA targets of PETISCO, we performed iCLIP using anti-TOFU-6 antibodies in embryos. This approach revealed highly specific enrichment of replication-dependent histone transcripts, with crosslinking sites concentrated in the 3' regions of these mRNAs, particularly 12 nucleotides upstream of the conserved stem-loop structure.