Effect of cycloheximide and growth factors on gene expression in quiescent mouse embryo fibroblasts

✍ Scribed by M. Subramaniam; G. Shanmugam

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 636 KB
• Volume: 126
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041260107

✦ Synopsis

Gene expression in quiescent mouse embryo fibroblasts was studied by labelling the cells with [14C] amino acids and analysing the proteins by electrophoresis in polyacrylarnide gradient gels containing sodium dodecyl sulfate. Cyclohexirnide (CHI pretreatment of the cells was found to induce the synthesis of four proteins of molecular weights 72,000, 68,000, 42,000, and 29,000. These proteins were induced by CH both in serum-arrested and serum-stimulated cells. Addition of platelet-derived growth factor to serumarrested quiescent cells also induced t h e synthesis of these proteins. Addition of CH and fetal calf serum (20%) to quiescent cells resulted in a dramatic increase in the synthesis of actin and another protein of molecular weight 29,000. The 29,000-dalton protein was present in higher quantities in t h e nuclei of induced cells. This protein appeared to be an early protein whose synthesis was transiently induced in quiescent cells within 3 hours of addition of 20% fetal calf serum (FCS). The synthesis of this protein was virtually turned off at 5-6 hours after the addition of serum. However, if CH or a combination of CH and FCS was present, a continuous synthesis of the 29 K protein was observed.

Regulation of cell proliferation is a highly complex process involving a variety of factors (Todaro et al., 1965;Holley and Kierman, 1968; Folkman and Moscona, 1978). Under unfavourable conditions, cells enter into a