A University of California, Berkeley team reported a protein engineering strategy that improves CRISPR‑Cas9 nuclear import by inserting multiple nuclear localization signals (NLS) into internal surface loops rather than appending long N‑ or C‑terminal tails. The modification increased nuclear delivery and enhanced gene editing in human T cells while preserving expression yields and stability. The group’s structural analysis identified permissive loop sites for NLS insertion, avoiding the expression penalties seen with excessive terminal NLS repeats. Christopher Doyle of IBC Services at WCG Clinical summarized the work and its implications for clinical gene‑editing manufacturing and potency. By improving the fraction of Cas9 that reaches nuclei, the approach could raise editing efficiency in therapeutic cell products and reduce required dosages—potentially lowering costs and improving safety margins for ex vivo and in vivo editing programs.