Provided herein are chemically ligated guide RNA oligonucleotides (lgRNA) which comprise two functional RNA modules (crgRNA and tracrgRNA) joined by non-nucleotide chemical linkers (nNt-linker), their complexes with CRISPR-Cas9, preparation methods of Cas9-lgRNA complexes, and their uses for prevention and treatments of herpesvirus infections in humans. Also disclosed are processes and methods for preparation of these compounds.