Table 2.

Neurodevelopmental studies of CTCF or cohesin complex knockout in animal model system

cKO mice model	Phenotype	Molecular finding	References
Nestin-driven Cre line- CTCF null specifically in neuronal precursor cells		CTCF necessary for the survival of the NPCs Upregulation of the p53 effector PUMA, resulting in apoptosis Regulates the balance between NPC proliferation and differentiation	[50]
Nex-Cre line- CTCF null specifically in postmitotic projection neurons	Postnatal growth retardation and abnormal behavior including changes in limb-clasping reflex Decrease in body weight and died approximately four weeks after the birth	Defects in dendritic arborization and synapse formation Regulates the stochastic expression of clustered protocadherins (Pcdhs) genes	[48]
Camkiia-cre line- CTCF null specifically in post-mitotic excitatory forebrain neurons	Deficits in learning and memory, including spatial memory and fear memory Died approximately four months of age	Defects in dendritic arborization and synapse formation Regulates the stochastic expression of clustered protocadherins (Pcdhs) genes Dysregulation of gene expression and chromatin looping in the BDNF and Arc	[51]
Tau-cre line-SMC3 null specifically in neurons	More anxiety-related behavior	Abnormal dendrite development and synaptic maturation Regulates neuronal development genes	[58]
Full body heterozygous deletion (Nipbl ±)	High mortality (75–80%) during the first weeks of life Small size, craniofacial anomalies, microbrachycephaly, heart defects, hearing abnormalities, delayed bone maturation and reduced body fat	Regulates protocadherin beta (Pcdhb) gene expression	[70]
knockout of genes SMC1 and SA (piggyback-induced) in drosophila		Reduced levels of the ecdysone receptor EcR-B1, a key regulator of axon pruning Disrupt axon pruning and causing neuroblast proliferation defects	[55]