Structure and promoter analysis of the gene encoding the mouse helix-loop-helix factor HES-5. Identification of the neural precursor cell-specific promoter element.
HES-5 is a mammalian basic helix-loop-helix factor that has a distant sequence homology to the product of the Drosophila pair-rule gene hairy. HES-5 mRNA is present exclusively in the developing nervous system, but its level decreases as neural differentiation proceeds. In this study, to characterize the molecular mechanism of the neural-specific expression of HES-5 we isolated the mouse HES-5 gene. This gene consists of three exons, and Southern blot analysis shows that it is a single copy gene. The transcription initiation site, determined by primer extension and reverse transcriptase-mediated polymerase chain reaction, is located 26 nucleotides downstream of a TATAbox. Transient transfection analysis shows that the upstream region of the HES-5 gene can direct efficient expression in neural precursor cells and moderate expression in undifferentiated NCB20 neuroblastoma-brain hybrid cells but not in glioma or fibroblast cells. The moderate level of expression in NCB20 cells decreases when differentiation into neuron-like cells is induced. Further promoter analysis shows that this undifferentiated neural-specific expression is mediated by the multiple GC stretches present in the HES-5 promoter. Gel mobility shift analysis suggests the presence of a neural precursor cell-specific protein that binds to the GC stretches. These results raise the possibility that HES-5 expression in the developing nervous system is regulated by the GC stretch-binding protein.
Institute for Immunology, Kyoto University Faculty of Medicine, Japan.
K
K
Takebayashi
C
C
Akazawa
S
S
Nakanishi
R
R
Kageyama
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics*; D004330:Drosophila / Q000235:genetics; D004622:Embryo, Mammalian / Q000378:metabolism; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D018257:Helix-Loop-Helix Motifs; D051379:Mice; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics*; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004268:DNA-Binding Proteins; D012097:Repressor Proteins; C489685:Hes5 protein, mouse