Clusterin (SGP-2) gene expression is cell cycle dependent in normal human dermal fibroblasts

In confluent human dermal fibroblasts brought to quiescence (G(0)) by serum starvation, the S phase peaked at 24 h after serum re-addiction and G(2)/M phase peaked at 36 h. This was confirmed by titration of h-gas1 mRNA (a ma rker of G(0) phase) and histone H3 (a marker of S phase). Clusterin mRNA ac cumulation progressively increased in cells proceeding to confluence after seeding and to quiescence upon serum starvation, and peaked at around G(0), in parallel with h-gas1 mRNA. At 6 h (roughly G(1) phase) clusterin transc ript formed a second peak, followed by a gradual decrease until 36 h. Corre spondence of clusterin protein accumulation to its mRNA occurred solely wit h regard to the G(0) peak but not to the second one. The possible meaning o f the cell cycle related clusterin gene expression is discussed. (C) 1999 F ederation of European Biochemical Societies.