A core region of the mafK gene IN promoter directs neurone-specific transcription in vivo.
BACKGROUND
MafK serves as a required subunit of erythroid transcription factor NF-E2 and also functions with various heterodimeric CNC family proteins. MafK expression begins in early mesoderm and is observed in mesenchymal and haematopoietic cells, as well as in neurones during mouse development. In mesodermal descendants, MafK mRNA begins with a distal first exon (called IM), whereas the mRNA in neurones begins with a proximal first exon (IN).


RESULTS
To elucidate the mechanisms that underlie the tissue-specific transcription of the mafK gene, and to gain insights into the functions of MafK during neural development, we analysed the activity of the mafK IN promoter. A detailed investigation of mafK expression in the embryonic spinal cord revealed that IN-initiated mRNA is expressed in the ventral side of the spinal cord. Transient transfection analysis of reporter plasmids bearing the IN promoter and upstream regions revealed that the 'core' region of this promoter (nt -67 to -9) is active and that its integrity is crucial for this activity. The core region was also capable of directing the tissue-specific transcription of a reporter gene in neural cells of the spinal cord in transgenic mice in vivo.


CONCLUSIONS
These results demonstrate that the specific expression of mafK in neural cells is determined, at least in part, by the core region of the IN promoter.
Motohashi
H
H
Center for Tsukuba Advanced Research Alliance and Institute of Basic Medical Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan.
Ohta
J
J
Engel
J D
JD
Yamamoto
M
M
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D005091:Exons; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007763:Lac Operon; D008156:Luciferases / Q000378:metabolism; D050985:MafK Transcription Factor; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D016716:PC12 Cells; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013116:Spinal Cord / Q000196:embryology / Q000378:metabolism; D014158:Transcription, Genetic
D050985:MafK Transcription Factor; D009687:Nuclear Proteins; D012333:RNA, Messenger; D008156:Luciferases