Rett syndrome(RTT),an X-linked dominant neurodevelopmental disorder characterized by regression of language,stereotype hand movement and loss of purposeful hand use,is primarily caused by mutation of menthyl-CpG-binding protein 2(MECP2).The 76 kb human MECP2 is characterized by three salient features: a very large intron 2(60 kb),an 8.5 kb 3′-UTR with highly conserved regions and different polyadenylation sites,and a 40 kb intergenic region separating MECP2 from the nearest upstream gene.There are two isoforms of MeCP2,MeCP2e1 and MeCP2e2.The differences between the two isoforms,the function of the 3′-UTR and the long-range cis-regulatory sequences in the intergenic region were extensively studied.In contrast to initial report,recent studies show that MeCP2 binds not only to methylated promoters and silence transcription,but also to the sites outside of genes containing only a few of CpG islands.Furthermore,MeCP2 can function as both an activator and a repressor of transcription.Abstract:SUMM ARY Rett syndrome(RTT),an X-linked dom inant neurodevelopmental d isorder characterized by regression of language,stereotype hand movement and loss of purposeful hand use,is primarily caused by mutation of menthyl-CpG-bind ing protein 2(MECP2).The 76 kb humanMECP2is characterized by three salient features: a very large intron 2(60 kb),an 8.5 kb 3′-UTR with highly conserved regions and d ifferent polyadenylation sites,and a 40 kb intergenic region separatingMECP2from the nearest up-stream gene.There are two isoforms ofMeCP2,MeCP2e1 and MeCP2e2.The d ifferences between the two isoforms,the function of the 3′-UTR and the long-range cis-regulatory sequences in the intergenic re-gion were extensively stud ied.In contrast to initial report,recent stud ies show thatMeCP2 binds not only to methylated promoters and silence transcription,but also to the sites outside of genes containing only a few of CpG islands.Furthermore,MeCP2 can function as both an activator and a repressor of transcrip-tion.
