Ileal reclamation of @entity3645 , a critical determinant of their enterohepatic circulation, is mediated primarily by the apical @entity1372 -dependent @entity6741 transporter ( @entity57564 = @entity57564 ). We have defined mechanisms involved in the transcriptional regulation of @entity57564 . The @entity57564 gene extends over 17 kilobases and contains five introns. Primer extension analysis localized two transcription initiation sites 323 and 255 base pairs upstream of the initiator @entity1853 . Strong promoter activity is imparted by both a 2.7- and 0.2-kilobase 5'-flanking region of @entity57564 . The promoter activity is cell line specific (Caco-2, not Hep-G2, HeLa-S3, or Madin-Darby @entity235 kidney cells). Four distinct specific binding proteins were identified by gel shift and cross-linking studies using Caco-2 or @entity35 ileal nuclear extracts. Two AP-1 consensus sites were identified in the proximal promoter. DNA binding and promoter activity could be abrogated by mutation of the proximal AP-1 site. Supershift analysis revealed binding of @entity1178 and @entity5019 to this AP-1 element. Co-expression of @entity1178 enhanced promoter activity in Caco-2 cells and activated the promoter in Madin-Darby @entity235 kidney cells. Region and developmental stage-specific expression of @entity57564 in the @entity35 intestine correlated with the presence of one of these DNA-protein complexes and both @entity5019 and @entity1178 proteins. A specific AP-1 element regulates transcription of the @entity35 @entity57564 gene.

The role of AP-1 in the transcriptional regulation of the @entity35 apical @entity1372 -dependent XXXX transporter.

@entity235 :: ('9615', 'Species') :: ['canine'] @entity1372 :: ('MESH:D012964', 'Chemical') :: ['sodium'] @entity5019 :: ('314322(Tax:10116)', 'Gene') :: ['c-Fos'] @entity1853 :: ('MESH:D008715', 'Chemical') :: ['methionine'] @entity1178 :: ('3725', 'Gene') :: ['c-Jun'] @entity57564 :: ('29500(Tax:10116)', 'Gene') :: ['SLC10A2', 'ASBT'] @entity6741 :: ('CHEBI:3098', 'Chemical') :: ['bile acid'] @entity35 :: ('10116', 'Species') :: ['rat'] @entity3645 :: ('MESH:D001647', 'Chemical') :: ['bile salts']
@entity6741 :: (CHEBI:3098,Chemical) :: ['bile acid']
