HIV-1 gp120 induces the activation of both c-fos and c-jun immediate-early genes in HEL megakaryocytic cells.

We have previously demonstrated that the addition in culture of recombinant HIV-1 IIIB envelope gp120 affects the survival/growth of pluripotent haemopoietic progenitors, and, in particular, of those committed towards the megakaryocytic lineage. To characterize some of the molecular mechanisms involved in this phenomenon, we investigated the expression of members of the activating protein-1 (AP-1) complex in the HEL megakaryoblastic cell line. Following the treatment of HEL cells with recombinant IIIB envelope gp120, we noticed: (i) increased levels of endogenous c-fos and c-jun mRNA and proteins, (ii) activation of both c-fos and c-jun promoters, and (iii) a very rapid stimulation of a MAPK/ERK pathway.