Immediate early gene c-fos regulates the synthesis of phospholipids but not of gangliosides.

Retinal ganglion cells isolated from chicks that in vivo were exposed to light have a higher phospholipid labeling capacity than those obtained from animals in the dark. Actinomycin D or a mixture of protein synthesis inhibitors or of antisense oligonucleotides to c-fos plus c-jun injected intraocularly 1 hr prior to the stimulation period, abolished the light-dark differences for phospholipids but not for gangliosides. Light stimulation induced the formation (and/or stabilization) of c-fos mRNA and of the protein c-Fos, indicating that immediate early gene induction, and consequently the synthesis of the protein(s) encoded, is essential to increase the synthesis of phospholipids but not of gangliosides. These results suggest a novel mechanism by which immediate early genes engram neural cells, modifying specifically the metabolism of cell constituents producing long-lasting changes in the cells.