Summary

The availability of synchronous cultures of untransformed CV-I cells has allowed analysis of the role of cell-substrate attachment in cell cycle progression as well as the ability of serum and SV40 infection to override the requirement for cell-substrate attachment. Attachment to a solid substrate is required for progression through G1. Prevention of attachment results in cell cycle arrest 30 min after cytokinesis. Serum is required for attachment, but increasing the serum concentration from 2 to 20 % does not enhance cell attachment, nor obviate its need for cell cycle progression. SV40 infection does not overcome the requirement of serum for attachment nor the need of attachment for normal cycling.