The regulation of the murine Hox-2.5 gene expression during cell differentiation.
The mouse Hox-2.5 gene containing a Drosophila Antennapedia-type homeobox sequence is expressed in a spatially and temporally restricted manner during embryogenesis. We found that the mouse embryonal carcinoma cell line P19 expresses Hox-2.5 during differentiation by the treatment with retinoic acid (RA). Expression of the Hox-2.5 gene was not detected in undifferentiated P19 cells, but detected 72 hours after treatment with RA. In order to analyze this inductive response, we first identified the Hox-2.5 transcription initiation site and a possible promoter region. Subsequently, we prepared constructs containing various Hox-2.5 DNA fragments fused to a firefly luciferase reporter gene and transfected these into undifferentiated or differentiating P19 cells. These studies have demonstrated that a region -279 to +15 with respect to the transcription initiation site has a differentiation-responsive promoter activity. Deletion analysis suggests that the sequences responsible for this induction are located in several distinct domains within the 294 bp promoter region. Two of the possible differentiation-responsive elements were identified by analysis of DNA-protein interactions, and in vivo competition assays lend support to the notion that these regions are involved in the differential expression of Hox-2.5 promoter activity.
Department of Biochemistry, Faculty of Medicine, University of Tokyo, Japan.
T
T
Kondo
N
N
Takahashi
M
M
Muramatsu
D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive; D002454:Cell Differentiation / Q000235:genetics*; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D005801:Genes, Homeobox; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D004247:DNA