Expression and phosphorylation of the replication regulator protein geminin

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• 作者：Kulartz ; Monika ; Kreitz ; Sandra ; Hiller ; Ekkehard ; Damoc ; Elena-Catalina ; Przybylski ; Michael ; et. al.
• 关键词：Cell cycle ; DNA-replication ; Replication&ndash ; regulation ; Geminin ; Phosphorylation ; Turnover ; Mass spectrometry
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2003
• 出版时间：May 30, 2003
• 年：2003
• 卷：305
• 期：2
• 页码：412-420
• 全文大小：419 K

文摘

It has been described that the replication regulator protein geminin is rapidly degraded at the end of mitosis and newly expressed at the beginning of the next S phase in the metazoan cell cycle. We have performed experiments to investigate the synthesis of geminin in cycling human HeLa cells. The levels of geminin-mRNA vary only modestly during the cell cycle with a 2–3-fold higher mRNA level at the G1/S phase transition, whereas newly synthesized geminin can only be detected in post-G1 phases. Surprisingly, geminin, once synthesized, does not remain stable, but is turned over during S phase with a half-life of 3–4h. We also show that geminin becomes phosphorylated as S phase proceeds and identify by MALDI mass spectrometry two specific major phosphorylation sites.