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Genomic Organization and Promoter Analysis of a Mouse Homeobox Gene, Hex
- Source :
- Journal of Biochemistry. 125:795-802
- Publication Year :
- 1999
- Publisher :
- Oxford University Press (OUP), 1999.
-
Abstract
- A homeobox gene, Hex, is mainly expressed in haematopoietic cells and hepatocytes. It is assumed to play a role in the early stage of differentiation of these cells. To understand the mechanisms involved in the regulation of the Hex gene expression in hepatocytes, we cloned and characterized the mouse Hex gene. The gene consists of four exons and three introns, and spans about 5.7 kb. All the exon-intron boundaries are consistent with the "GT-AG" rule. A single transcription start site was identified by primer extension and S1 mapping analyses. Although the 5'-flanking region is G/C rich (69%), it contains probable "TATA and CCAAT" boxes. Potential binding sequences for transcriptional regulatory proteins including Sp1 and AP-2 are also present in this region. Functional analysis of the Hex promoter was performed by transfecting MH1C1, HeLa, COS-7, and Caco-2 cells with Hex promoter region-luciferase constructs. We found three possible positive regulatory regions, comprising of nucleotides -199 and -172, -154 and -133, and -105 and -68, respectively, required for Hex gene expression in MH1C1 cells by analyses of a series of 5'-deletion constructs of the fusion genes. The activities of these constructs were extremely low in HeLa, COS-7, and Caco-2 cells suggesting that they possess cell-type specificity. Further analysis revealed two GC boxes, GC box1 and GC box2, at nucleotides -197 to -188 and -176 to -167, respectively, necessary for Hex gene expression. Thus, multiple regulatory elements contribute to the Hex gene expression in hepatocytes.
- Subjects :
- DNA, Complementary
Molecular Sequence Data
Gene Expression
Biology
Transfection
Biochemistry
Cell Line
Fusion gene
Mice
Gene expression
Animals
Humans
Cloning, Molecular
Luciferases
Promoter Regions, Genetic
CDX2
Molecular Biology
Gene
DNA Primers
Genomic organization
Regulation of gene expression
Genome
Base Sequence
integumentary system
Genes, Homeobox
Exons
General Medicine
Molecular biology
Introns
Liver
Regulatory sequence
COS Cells
Mutation
embryonic structures
Homeobox
Caco-2 Cells
HeLa Cells
Subjects
Details
- ISSN :
- 0021924X
- Volume :
- 125
- Database :
- OpenAIRE
- Journal :
- Journal of Biochemistry
- Accession number :
- edsair.doi.dedup.....96ca3edee70a0c28ba164e1a35dd430c