Differential expression of intracisternal A-particle transcripts in immunogenic versus tumorigenic S49 murine lymphoma cells
| Autor: | Jacob Hochman, Kira K. Lueders, Efrat Rorman, Allan Bar-Sinai, Efrat Braun |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
DNA
Complementary Lymphoma Transcription Genetic Lymphocyte Molecular Sequence Data Gene Products gag Endogeny Biology Mice Complementary DNA Virology Sequence Homology Nucleic Acid medicine Cell Adhesion Tumor Cells Cultured Cytotoxic T cell Animals Amino Acid Sequence RNA Messenger Gene Peptide sequence Base Sequence Sequence Homology Amino Acid Molecular biology Genes gag medicine.anatomical_structure Genes Intracisternal A-Particle Intracisternal A-Particle Differential display technique Sequence Alignment |
| Zdroj: | Virology. 277(1) |
| ISSN: | 0042-6822 |
| Popis: | Tumorigenic S49 mouse lymphoma cells (T-25) were compared to their nontumorigenic (immunogenic) substrate-adherent descendants (T-25-Adh), using the differential display technique. A 784-bp fragment with 92% sequence homology to the intracisternal A-particle (IAP) element family was isolated from the latter cells. IAP sequences are endogenous, noninfectious retroviral elements that can undergo transpositions and act as mutagens. Expression of IAP transcripts (as detected by the isolated fragment) was 5- to 10-fold higher in T-25-Adh cells than in T-25 cells. IAP RT-PCR cDNA clones derived from the immunogenic T-25-Adh cells, but not from T-25 cells, contain two distinctive motifs: (i) a motif characteristic of IAP elements expressed in lymphoid cells (lymphocyte specific, LS); (ii) a nonapeptide sequence known to stimulate cytotoxic T lymphocytes in a leukemia cell line expressing IAP sequences. In addition, expression of transcripts containing these motifs is enhanced in the immunogenic cells as opposed to the tumorigenic cells. Furthermore, one of the IAP elements (belonging to the LS1 subfamily) is specifically hypomethylated in the DNA of the immunogenic cells. The above-mentioned relationship was strengthened when tumorigenic revertants derived from T-25-Adh cells, as well as independently selected tumorigenic and immunogenic S49 sublines, were studied. In all cases, enhanced immunogenicity was linked to the up-regulation of specific IAP elements. No transpositions of LS1 elements were observed among the different sublines studied. These findings suggest that, in the S49 lymphoma, selectively expressed IAP retroviral elements may function in a tumor suppressive capacity by affecting the immunogenic potential of these cells. |
| Databáze: | OpenAIRE |
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