Since there was a significant reduction in the expression of Sin3A at the cellular level after cell differentiation in NTera-2 cells, we next investigated regional alterations in chromatin around the STAT3-binding site at the promoter and transcription initiation sites of GFAP before and after astrocyte-like differentiation. To ascertain local changes in transcription factor binding, we performed ChIP assays with specific antibodies against Sin3A and MeCP2. In addition, the binding of these two co-repressors was quantitated by a real-time PCR using primers spanning from the STAT3 binding site at the promoter to exon 1 relative to the transcription start site of GFAP (primer sets a-g in Fig. 4A ). In addition, a pair of primer, h (Fig. 4A) , located between exons 6 and 7 near the end of GFAP gene and remote from the transcription regulatory region, served as a negative control. It was found that upon cellular differentiation, the binding of Sin3A significantly and specifically diminished around the STAT3 binding site about 1500 bp upstream of the GFAP start site in the promoter region (primer sets a-c in Fig. 4A) (Fig. 4B ). In addition, we also identified that Sin3A occupancy at primer set g in the vicinity of exon 1 was strongly reduced after cell differentiation, whereas binding levels of Sin3A across the exon 1 locus (primer sets e and f) were not altered. Since Sin3A lacks an intrinsic DNA-binding capacity, it must target itself to promoters via interactions with other DNA-binding or adaptor proteins, such as MeCP2, a methyl-CpG-binding protein, which was reported to interact with Sin3A in Xenopus laevis oocytes [52] . To test the possibility that MeCP2 may target Sin3A to the GFAP promoter, we performed a ChIP analysis to inspect the binding of MeCP2 around the STAT3-binding site at the GFAP promoter and in the proximity of exon 1 before and after cell differentiation. As shown in Fig. 4B , the level of specific binding between MeCP2 and the STAT3-binding site at the GFAP promoter (primer sets a-c) and in the proximity of exon 1 (primer sets d-g, except site e) regions of GFAP in undifferentiated NTera-2 cells was substantially reduced in differentiated astrocyte-like cells. As the binding patterns for MeCP2 and Sin3A at the GFAP promoter and exon 1 occurred in a coordinated manner, these results suggest that MeCP2 may be responsible for recruiting the Sin3A co-repressor complex to the area surrounding the GFAP promoter.