Figure 3.

cAMP-induced transcriptional activation of HIV-1 and CXCR4 promoters is specifically mediated by CREB-1. (A) In comparison with forskolin-stimulated cells transfected with parental LTR-luc constructs alone, cells with LTR-luc and CREB-133 or KCREB constructs exhibit diminution in firefly luciferase expression. All firefly luciferase readings were normalized to Renilla readings by cotransfecting cells with the pRL-TK Renilla luciferase construct and expressed as ratios of forskolin-treated to untreated samples. (B) qRT-PCR assays revealed that in comparison with untransfected untreated and untransfected forskolin-treated samples, pKCREB and pCREB-133 transfected samples showed diminution in CXCR4 transcript levels. Results were normalized to RPLPO expression and expressed in linear scale as fold over untreated untransfected samples. Asterisks indicate significance of P < 0.05 using Student’s t–test.