5YEF:
reference: Molecular mechanism of directional CTCF recognition of a diverse range of genomic sites., Yin M, Wang J, Wang M, Li X, Zhang M, Wu Q, Wang Y, Cell Res. 2017 Nov;27(11):1365-1377. doi: 10.1038/cr.2017.131. Epub 2017 Oct 27. PMID: 29076501

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