Identification of the SL3-3 virus enhancer core as a T-lymphoma cell-specific element.
Transient expression assays were used to determine the sequences within the long terminal repeat (LTR) that define the high activity in T-lymphoma cells of the leukemogenic SL3-3 virus in comparison with that of the nonleukemogenic Akv virus. Each of these viruses contains sequences related to the consensus element, the enhancer core. The SL3-3 and Akv enhancer cores differ at a single base pair. Substitution of the Akv core element into the SL3-3 LTR decreased expression in T-lymphoma cells but not in other cell types. Likewise, substitution of the SL3-3 core sequence into the Akv LTR increased expression in T-lymphoma cells but not in other types of hematopoietic cells. These data indicate that the SL3-3 enhancer core sequence functions better than that of Akv in T-lymphoma cells, but in other hematopoietic cell types the two are approximately equivalent. Competition DNA-protein binding assays were used to assess what nuclear factors from T-lymphoma lines and non-T lines bound to the SL3-3 and Akv core elements. Factors were detected that bound specifically to either the SL3-3 or Akv core but not to the other. Another factor was detected that bound equally well to both. However, none of these factors was specific to T-lymphoma cells.
Boral
A L
AL
Department of Genetics, Albert Einstein College of Medicine, Bronx, New York 10461.
Okenquist
S A
SA
Lenz
J
J
D000818:Animals; D015342:DNA Probes; D004279:DNA, Viral / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D009052:Leukemia Virus, Murine / Q000235:genetics*; D008223:Lymphoma / Q000382:microbiology*; D009687:Nuclear Proteins / Q000378:metabolism; D010957:Plasmids; D012091:Repetitive Sequences, Nucleic Acid; D013601:T-Lymphocytes / Q000382:microbiology*; D014407:Tumor Cells, Cultured
D015342:DNA Probes; D004279:DNA, Viral; D009687:Nuclear Proteins