Activation of gene transcription by IL-4, IL-13 and IFN-gamma through a shared DNA binding motif.

Both interleukin-4 (IL-4) and interleukin-13 (IL-13) induce the transcription factor NF-IL4 (nuclear factor IL-4) which preexists in an inactive form and binds to an IL-4 responsive element (IL-4RE) in the promoter regions of IL-4/IL-13-dependent genes. UV-crosslinking and SDS gel electrophoresis indicate that NF-IL4 consists of at least two DNA-binding components of 50 kDa and 100-130 kDa. The IL-4 responsive element is also recognized by an interferon-gamma (IFN-gamma)-induced DNA binding protein for which a Mr of 50 kDa has been determined.

Human interleukin-13 activates the interleukin-4-dependent transcription factor NF-IL4 sharing a DNA binding motif with an interferon-gamma-induced nuclear binding factor.

The effects of interleukin-13 (IL-13) and interleukin-4 (IL-4) on cellular functions were shown to be quite similar. We provide evidence that in monocytes as well as in T lymphocytes both IL-4 and IL-13 activate the same recently identified transcription factor NF-IL4 which binds to the specific responsive element IL-4RE. In addition, we show that a nuclear factor activated by interferon-gamma also interacts with the IL-4RE.

Different activation of Epstein-Barr virus immediate-early and early genes in Burkitt lymphoma cells and lymphoblastoid cell lines.

Specific expression of the Epstein-Barr virus (EBV) immediate-early and early gene products Zta, Rta, I'ta, and MSta by a recombinant vaccinia virus system allowed us to analyze the first steps in the induction of the lytic cycle in EBV-infected Burkitt lymphoma (BL) cells and lymphoblastoid cell lines (LCLs). Significant differences in the induction of early genes were found between these cell types: whereas in BL cells the trans activator Zta was found to induce key steps of the early lytic cycle, only minor activities of Zta were noted in LCLs. Contrary to Zta, the trans activator Rta was found to be highly effective in LCLs.

The lytic transition of Epstein-Barr virus is imitated by recombinant B-cells.

Lytic transition of Epstein-Barr virus (EBV) is initiated by distinct immediate early regulators of the viral cycle, in synchronization to temporary, permissive conditions during host cell differentiation. We developed eukaryotic vectors suitable to imitate the processes involved in lytic transition in cell culture systems. Two stable B cell lines were established: R59Z activator cells were used to induce lytic EBV expression in a constitutive manner by the production of the BZLF 1 trans-activator (Zta).