Analysis of proteins associated with chromosome condensation in baby hamster kidney cells

To identify proteins concerned with chromosome condensation processes, we used a temperature-sensitive mutant, tsBN2 derived from BHK21, in which premature chromosome condensation occurred at high temperature. When the proteins synthesized in tsBN2 during the induction of premature chromosome condensation were analyzed by two-dimensional gel electrophoresis, we found that an acidic protein with a molecular weight of 35,000 was specifically associated with chromosome condensation. In the normal cell cycle, this protein was synthesized from the G2 through the M phase. The protein was located mainly in the chromosome fraction and was phosphorylated.