Expression of the Woodchuck N-myc2 Retroposon in Brain and in Liver Tumors Is Driven by a Cryptic N-myc Promoter
| Autor: | Marie-Annick Buendia, Geneviève Fourel, B C Tennant, Catherine Transy |
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| Rok vydání: | 1992 |
| Předmět: |
Untranslated region
Transcription Genetic TATA box Molecular Sequence Data Genes myc Biology Methylation Proto-Oncogene Mas Cell Line Exon Mice Sequence Homology Nucleic Acid Gene expression Tumor Cells Cultured Animals Humans Amino Acid Sequence Promoter Regions Genetic Gene Molecular Biology Regulation of gene expression Genetics Terminator Regions Genetic Base Sequence Retroposon Liver Neoplasms Brain DNA Cell Biology Molecular biology Gene Expression Regulation Neoplastic Gene Expression Regulation Regulatory sequence Organ Specificity Marmota DNA Transposable Elements Dinucleoside Phosphates Research Article |
| Zdroj: | Molecular and Cellular Biology. 12:5336-5344 |
| ISSN: | 1098-5549 |
| DOI: | 10.1128/mcb.12.12.5336-5344.1992 |
| Popis: | The woodchuck intronless proto-oncogene N-myc2 was initially discovered as a frequent target site for hepadnavirus integration in hepatocellular carcinoma. N-myc2 possesses characteristics of a functional retroposon derived from the woodchuck N-myc gene. We have investigated the regulatory signals governing N-myc2 expression and found that a short promoter, including a variant TATA box and potential binding sites for several transcription factors, is localized in the N-myc2 sequences homologous to the 5' untranslated region of the second N-myc exon. The corresponding region in the intron-containing woodchuck N-myc gene also exhibited promoter activity in transient transfection assays. The high evolutionary conservation of these sequences in mammalian N-myc genes suggests that they contain a cryptic N-myc promoter which may be unmasked in the particular context provided by the N-myc2 retroposon. Although N-myc2, like the woodchuck N-myc gene, contributes to an extended CpG island and was found constitutively hypomethylated, it presents a highly restricted expression pattern in adult animals. Whereas the intron-containing N-myc gene is expressed at low levels in different tissues, N-myc2 mRNA was detected only in brain tissue, raising questions about the functional significance of the maintenance of a second N-myc gene in the woodchuck genome. |
| Databáze: | OpenAIRE |
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