CCCTC Binding Factor Like Protein (CTCFL)

CTCF and CTCFL are normally expressed in a mutually exclusive pattern that correlates with resetting of methylation marks during male germ cell differentiation.

The deduced 663-amino acid protein contains 11 central ZFs like CTCF, but it has unique N and C termini. EMSA analysis showed an interaction with testis DNA. Northern blot and RT-PCR analyses revealed that expression of CTCFL is testis-specific in humans and mice. Immunohistochemical and Western blot analyses showed expression of an approximately 83-kD protein primarily in the cytoplasm of spermatocytes, with some nuclear expression detected. CTCF, on the other hand, was restricted to the nucleus and was expressed in somatic cells.