The study demonstrates that a dCas9-VP64 fusion protein, directed by single or multiple guide RNAs (gRNAs), can activate the expression of specific endogenous human genes. The dCas9-VP64 fusion was constructed and tested for its ability to activate the human VEGFA gene using 16 pre-validated gRNAs. The results showed that 15 out of 16 gRNAs significantly increased VEGFA protein expression in human 293 cells. Similar results were observed for the NTF3 gene, with six sgRNAs inducing significant increases in transcript levels. The study also found that multiple sgRNAs could synergistically activate gene expression, suggesting that RNA-guided activators can function efficiently in a single cell. The findings provide proof-of-principle that CRISPR-Cas systems can be used to target heterologous effector domains in human cells, opening up new possibilities for biological research and synthetic biology.The study demonstrates that a dCas9-VP64 fusion protein, directed by single or multiple guide RNAs (gRNAs), can activate the expression of specific endogenous human genes. The dCas9-VP64 fusion was constructed and tested for its ability to activate the human VEGFA gene using 16 pre-validated gRNAs. The results showed that 15 out of 16 gRNAs significantly increased VEGFA protein expression in human 293 cells. Similar results were observed for the NTF3 gene, with six sgRNAs inducing significant increases in transcript levels. The study also found that multiple sgRNAs could synergistically activate gene expression, suggesting that RNA-guided activators can function efficiently in a single cell. The findings provide proof-of-principle that CRISPR-Cas systems can be used to target heterologous effector domains in human cells, opening up new possibilities for biological research and synthetic biology.