In mouse embryonic stem cells, the regulators of transposable elements are not well known. Here, we studied the proteins regulating mammalian-wide interspersed repeat (MIR), a short-interspersed nuclear elements (SINE) family using the CAPTURE2.0 system. We generated cell lines expressing biotinylated dCas9 protein and MIR-targeting sgRNAs, performed biotin pulldown to isolate MIR-associated proteins, and analyzed them using mass spectrometry.