To address the impact of MORC2 O-GlcNAcylation on biological behavior of breast cancer cells, we first knocked out (KO) endogenous MORC2 in LM2–4175 and BT549 cells using CRISPR-Cas9 technology [38], and then reintroduced empty vector pMSCV or Flag-MORC2 (WT, T556A or T556D) into resultant MORC2 KO cells by lentiviral infection (Fig. 3A). Here, MORC2 is linked to breast cancer.