dCas9-KRAB mRNA encodes the dCas9-KRAB fusion protein, a tool for gene silencing and transcriptional repression. The dCas9 (dead Cas9) component targets DNA precisely without cutting, while the KRAB (Krüppel-associated box) domain recruits complexes to inhibit gene expression. Delivered as mRNA, dCas9-KRAB ensures rapid, high transient expression without nuclear uptake, making it ideal for research in gene function, genetic diseases, and therapeutic development. Croyez’s dCas9-KRAB mRNA is generated through in vitro transcription, with a Cap1-modified 5' end and a poly(A) tail at the 3' end to mimic mature mRNAs. These optimizations enhance stability and performance, ensuring the mRNAs function like natural mature mRNAs in cells.