title: Mesodermal- vs. neuronal-specific expression of MafK is elicited by different promoters.
abstract: BACKGROUND
  Small members of the Maf family of transcriptional regulatory proteins share similar basic-leucine zipper domains but have no intrinsic ability to activate transcription. One member of the family (MafK) has been shown to mediate both negative and positive regulation: in addition to forming a homodimer which represses transcription, MafK can also form a heterodimer with p45 (the large subunit of erythroid transcription factor NF-E2) to activate transcription.
  
  
  RESULTS
  We examined the expression of mafK during murine development. mafK mRNA was first detected in 7.5 days post coitus (dpc) embryonic mesoderm and persisted in mesodermal derivatives (mesenchymal and haematopoietic cells) thereafter. However, around 13 dpc mafK was also strongly induced in neuronal cells and it is broadly expressed in neurones in postnatal mouse. The neuronal expression of mafK is directed by a distinct promoter located 6 kbp 3' to the mesoderm-specific promoter. mafK in neurones associates with a different partner molecule from p45. In transgenic mice, a regulatory domain in the immediate vicinity of the mesodermal promoter was found to direct mesenchymal, but not haematopoietic, expression of mafK.
  
  
  CONCLUSIONS
  The cell type- and developmental stage-specific expression of MafK suggests that, in addition to its demonstrated role in erythroid transcriptional regulation, MafK also plays an important regulatory role in other mesodermally and neuroectodermally derived tissues during mouse embryonic development.
authors.affiliation: Department of Biochemistry, Tohoku University School of Medicine, Aoba-ku, Sendai, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Motohashi
authors.forename: K
authors.initials: K
authors.lastname: Igarashi
authors.forename: K
authors.initials: K
authors.lastname: Onodera
authors.forename: S
authors.initials: S
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Ohtani
authors.forename: M
authors.initials: M
authors.lastname: Nakafuku
authors.forename: M
authors.initials: M
authors.lastname: Nishizawa
authors.forename: J D
authors.initials: JD
authors.lastname: Engel
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D001483:Base Sequence; D019281:Dimerization; D004475:Ectoderm / Q000378:metabolism; D005091:Exons / Q000235:genetics; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D017403:In Situ Hybridization; D016350:Leucine Zippers; D008099:Liver / Q000196:embryology; D050985:MafK Transcription Factor; D008648:Mesoderm / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009420:Nervous System / Q000196:embryology; D009474:Neurons / Q000378:metabolism; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012333:RNA, Messenger / Q000302:isolation & purification; D014018:Tissue Distribution
chemical_list: D050985:MafK Transcription Factor; D009687:Nuclear Proteins; D012333:RNA, Messenger