Fig. 2

The RATS element mediates repression and derepression of the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR). (A) Cloramphenicol acetyl transferase (CAT) assays of oocytes used in transactivation experiments. In a first injection, buffer (−) or protein extract from resting peripheral blood (PB) T cells (T0) or cord blood T cells (C0) were injected into the oocyte cytoplasm. 2 hr later, the target genes pUC-BENN-CAT, 2xRATS-CAT, or 5xRATS-CAT were injected into the oocyte nucleus. When indicated, extract from PB T cells stimulated for 8 hr in the absence (T8) or presence of the immunosuppressive drug FK506 (T8^FK) or from 4 hr-stimulated, purified memory T cells (M4) was added in a third, cytoplasmic injection. (B) Similar transactivation assay as in (A) using the 4xPU-CAT gene containing the IL-2 PRRE and proteins from peripheral, resting (T0) or 8 hr-stimulated (T8) WBC or extracts from fluorescence-activated cell sorter (FACS)-purified CD4⁺/CD45RO⁻ (RO⁻) and CD4⁺/CD45RO⁺ (RO⁺) cells. (C) FACS analysis of PB and cord blood T cells, using CD4 (green) and CD45RO (red) antibodies. N, naive; M, memory.