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Background: CTCF is a versatile zinc finger DNA-binding protein that functions as a highly conserved epigenetic transcriptional regulator.CTCF is known to act as a chromosomal insulator, bind promoter regions, and facilitate long-range chromatin interactions.In mammals, CTCF is active in the regulatory regions of some genes that exhibit genomic imprinting, acting as insulator on only one parental allele to facilitate parent-specific expression.CTCF plays a critical role in transcriptional regulation in vertebrates.The nucleosome is the fundamental packing unit of DNAs in eukaryotic cells.Its detailed positioning on the genome is closely related to chromosome functions.GC content is two transformations of dinucleotide composition and the frequency of eleven 4-bp sequences.GC content is the most important features.Methods: The insulator data come from CCCTC-binding factor database (CTCFBSDB, http://insulatordb.uthsc.edu/browse.php).Nucleosome datasets come from Dustins paper.The GC content of insulator was calculated and average nucleosome occupancy was also calculated in the l000bp of upstream and downstream of start site and termination site of insulator, This is computational formula of GC content:GC% =G+C/A+T+G+C ×100% Results: The results showed that the GC content in the insulator is higher than the average level in human, and the nucleosome average occupancy is higher in insulator than blanks both insulator.Conclusions: The insulator sequence in which GC content is higher benefits the bending of DNA sequence and form a compact nucleosome around histone octamer, and the insulator in which the nucleosome occupancy is higher is beneficial to isolate two transcriptional function region .