title: Serotonin transporter mRNA levels are associated with the methylation of an upstream CpG island.
abstract: The serotonin reuptake transporter (5HTT) is thought to be the principal regulator of serotonergic activity and epigenetic effects at this locus are thought to be important moderators of vulnerability to neuropsychiatric illness. In attempt to understand the basis of this regulation, several gene polymorphisms that affect 5HTT mRNA levels have been described. But to date, no clear mechanism linking these polymorphisms to vulnerability to epigenetic effects have been described. In this communication, we describe a CpG island in the 5' region of the 5HTT gene that contains an alternative exon 1 and possible promoter for 5HTT. We then confirm the existence of this transcript and ascertain the methylation status of this CpG island in 49 lymphoblast cell lines and analyze the relationship between methylation and 5HTT mRNA levels. We demonstrate that methylation at this CpG island is associated with decreased levels of 5HTT mRNA, but that this effect is evident only when 5HTTLPR genotype is taken into account. We suggest that these findings have significant implications for the understanding of the role of this locus in behavioral illness.
authors.affiliation: Department of Psychiatry, The University of Iowa, Psychiatry Research/MEB, Iowa City, Iowa, USA. robert-philibert@uiowa.edu
authors.forename: Robert
authors.initials: R
authors.lastname: Philibert
authors.forename: Anup
authors.initials: A
authors.lastname: Madan
authors.forename: Allan
authors.initials: A
authors.lastname: Andersen
authors.forename: Remi
authors.initials: R
authors.lastname: Cadoret
authors.forename: Hans
authors.initials: H
authors.lastname: Packer
authors.forename: Harinder
authors.initials: H
authors.lastname: Sandhu
mesh_terms: D001483:Base Sequence; D002460:Cell Line; D018899:CpG Islands; D019175:DNA Methylation; D018076:DNA, Complementary / Q000235:genetics; D044127:Epigenesis, Genetic; D005091:Exons; D005824:Genetics, Behavioral; D005838:Genotype; D006801:Humans; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D050486:Serotonin Plasma Membrane Transport Proteins