Alleviating transcriptional inhibition of the norepinephrine slc6a2 transporter gene in depolarized neurons.
Recent studies have brought to light additional experimental information, namely, that the MeCP2 protein complex is not only capable of associating with members of the ATPase-dependent bromodomain family, but also found on nonmethylated genomic sequences. These unexpected results are indicative of a multifunctional role for MeCP2, more importantly; our view of the molecular mechanisms that regulate gene activity may not be necessarily distinguishable. Depolarized mouse neuronal cortical cells were examined for increased Slc6a2 mRNA synthesis, changes in CpG methylation status using bisulfite sequencing, and binding of MeCP2 and Smarca2 on the Slc6a2 promoter sequence by chromatin immunopurification strategies. Increased Slc6a2 gene expression in response to membrane depolarization was strongly correlated with the dissociation of MeCP2 and Smarca2 complex on the unmethylated gene. We identified that gene expression in neuronal cortical cells involves increased histone hyperacetylation on the Slc6a2 promoter, which is commensurate with the recruitment of SP1 and RNA Polymerase II and is inversely correlated with H3K9 trimethylation. We hypothesize that the MeCP2 corepressor is capable of associating with multiple forms of SWI/SNF to remodel chromatin for important regulatory roles. The results of our experiments indicate that these proteins are asymmetrically bound to chromatin independent of DNA methylation and not inevitably diametrically opposed. These results now begin to offer a new perspective on the mechanism of Slc6a2 gene regulation.
Harikrishnan
K N
KN
Epigenetics in Human Health and Disease Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria 3004, Australia.
Bayles
Richard
R
Ciccotosto
Giuseppe D
GD
Maxwell
Scott
S
Cappai
Roberto
R
Pelka
Gregory J
GJ
Tam
Patrick P L
PP
Christodoulou
John
J
El-Osta
Assam
A
D000818:Animals; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D051548:Histone Acetyltransferases / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000235:genetics; D051783:Methyl-CpG-Binding Protein 2 / Q000235:genetics / Q000378:metabolism; D008745:Methylation; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D050484:Norepinephrine Plasma Membrane Transport Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics*
C497393:Mecp2 protein, mouse; D051783:Methyl-CpG-Binding Protein 2; D050484:Norepinephrine Plasma Membrane Transport Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C493228:Slc6a2 protein, mouse; C499503:Smarca2 protein, mouse; D014157:Transcription Factors; D051548:Histone Acetyltransferases; D009638:Norepinephrine