. Author manuscript; available in PMC: 2019 Feb 14.

Published in final edited form as: Bioessays. 2010 Jan;32(1):37–50. doi: 10.1002/bies.200900118

Table 1.

Comparison of the features of CTCF and BORIS

Features	CTCF	BORIS (CTCFL)
Expression pattern	Ubiquitously expressed in various tissues and cells, in different organisms,⁽¹¹¹⁾ except primary spermatocytes⁽²⁸⁾	Primarily in spermatocytes in the testes of therian mammals in a mutually exclusive fashion with CTCF.^(22,28) Activated in a wide range of human cancers.^(116–118)
Localization	Nuclear⁽¹¹¹⁾	Nuclear and cytoplasmic.⁽²⁸⁾
Functions	Growth, proliferation, apoptosis, differentiation, imprinting, X-chromosome inactivation, genome integrity, candidate tumor suppressor^{(14,16,20,22,51)}	Linked with epigenetic reprogramming during germ-line development.^(22,28) Can function as a dominant-negative version of CTCF.
Identified orthologs	Chicken,⁽¹¹¹⁾ human,⁽⁴⁷⁾ mouse,⁽⁴⁷⁾ Xenopus,⁽¹¹²⁾ Drosophila,⁽¹¹³⁾ zebrafish,⁽¹¹⁴⁾ cattle,⁽¹¹⁵⁾ tammar wallaby,⁽¹¹⁵⁾ platypus,⁽¹¹⁵⁾ central bearded dragon⁽¹¹⁵⁾	Human,⁽²⁸⁾ mouse,⁽²⁸⁾ cattle,⁽¹¹⁵⁾ tammar wallaby,⁽¹¹⁵⁾ platypus,⁽¹¹⁵⁾ central bearded dragon⁽¹¹⁵⁾
Molecular mechanisms	Gene activation, repression, insulation and silencing^{(14,16,20,22,51)}	Initiation of methylation⁽¹¹⁹⁾ or de-methylation events^(117,120) in context-dependent manners
CTCF target sequences	Recognizes and binds to highly diverse sequences usually in methylation-sensitive manners^(16,20–22)	Likely to recognize the same set of DNA targets as CTCF^(22,28)