Figure 7.

Requirement of Hus1 for Rad17 phosphorylation. (A) Mouse Hus1^−/− p21^−/− cells (BS-1/pCaggs) or Hus1^−/− p21^−/− cells complemented with Hus1 (BS-1/pCaggs-Hus1) were untreated or treated with HU (1 mM for 24 h) or UV (80 J/m², harvested after 2 h). Extracts of these cells were analyzed by immunoblotting with the antibodies to Rad9 and actin. (B) Hus1^−/− p21^−/− cells or Hus1^−/− p21^−/− cells complemented with Hus1 were untreated or treated with HU as in A. Fractions from these cells were analyzed by immunoblotting. (C) The extracts described in A were analyzed by immunoblotting with antibodies to Rad17, p-S635 of Rad17, and actin. (D) Hus1^−/− p21^−/− cells or Hus1^−/− p21^−/− cells complemented with Hus1 were untreated or treated with 20 Gy of γ-IR and collected at the indicated times after irradiation. Extracts of these cells were analyzed by immunoblotting as in C.