A serum factor requirement for the passage of cultured Vero cells through G2

✍ Scribed by Dean L. Engelhard; Mao Jen-Hao

• Publisher: John Wiley and Sons
• Year: 1977
• Tongue: English
• Weight: 978 KB
• Volume: 90
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1040900216

✦ Synopsis

Abstract

When Vero cells, a line derived from an African Green Monkey kidney, are grown under conditions where the saturation density is limited by serum, they deplete the growth medium of a factor necessary for cell division. The factor is a component of serum. When Vero cells are plated at low density (2 × 10^4^/cm^2^) in this depleted growth medium (after dialysis against serum‐free Dulbecco's Modified Eagle's Medium) they initiate an unbalanced program of growth. Protein synthesis proceeds at the same rate as parallel cells in fresh serum, and the cells accumulate protein as a function of time. DNA synthesis is also initiated in these cells, and the amount of DNA per cell increases for the next four days after plating. However the cells quickly stop dividing. Measurements of DNA per cell using microspectrofluorometry show that the cells are accumulating in the late S and G~2~ period during this time. Thus we conclude that these cells cannot pass through a transition point in G~2~. When fresh serum is added to cells after three days in depleted growth medium, they divide before they begin to synthesize DNA. This further confirms that they are in late S and G~2~. Cell division is promoted in Vero cells in depleted growth medium by bovine fetuin, and to a lesser extent by bovine albumin. Cell division is not promoted by insulin, hydrocortisone, dexamethasone, linolenic acid, calcium, and trypsin inhibitor from ovomucoid. From these data we conclude that transit through G~2~ requires the presence of an extracellular factor.