Authors: Tschöp, Katrin¹; Müller, Gerd A.¹; Grosche, Jens²; Engeland, Kurt¹

Source: FEBS Journal, Volume 273, Number 8, April 2006 , pp. 1681-1695(15)

Publisher: Wiley-Blackwell

Abstract:

Cyclins form complexes with cyclin-dependent kinases. By controlling activity of the enzymes, cyclins regulate progression through the cell cycle. A- and B-type cyclins were discovered due to their distinct appearance in S and G₂ phases and their rapid proteolytic destruction during mitosis. Transition from G₂ to mitosis is basically controlled by B-type cyclins. In mammals, two cyclin B proteins are well characterized, cyclin B1 and cyclin B2. Recently, a human cyclin B3 gene was described. In contrast to the expression pattern of other B-type cyclins, we find cyclin B3 mRNA expressed not only in S and G₂/M cells but also in G₀ and G₁. Human cyclin B3 is expressed in different variants. We show that one isoform remains in the cytoplasm, whereas the other variant is translocated to the nucleus. Transport to the nucleus is dependent on three autonomous nonclassical nuclear localization signals that where previously not implicated in nuclear translocation. It had been shown that cyclin B3 coimmunoprecipitates with cdk2; but this complex does not exhibit any kinase activity. Furthermore, a degradation-resistant version of cyclin B3 can arrest cells in G₁ and G₂. Taken together with the finding that cyclin B3 mRNA is not only expressed in G₂/M but is also detected in significant amounts in resting cells and in G₁ cells. This may suggest a dominant-negative function of human cyclin B3 in competition with activating cyclins in G₀ and the G₁ phase of the cell cycle.

Keywords: cell cycle; cyclin B3; mRNA expression; nuclear localization signal

Document Type: Research article

DOI: http://dx.doi.org/10.1111/j.1742-4658.2006.05184.x

Affiliations: 1: Innere Medizin II, Max-Bürger-Forschungszentrum, Universität Leipzig, Germany 2: Paul-Flechsig-Institut für Hirnforschung, Universität Leipzig, Germany

Publication date: 2006-04-01

Related content

• In this: publication
• By this: publisher
• In this Subject: Anatomy & Physiology ,  Biology ,  Chemistry (General) ,  Biochemistry
• By this author: Tschöp, Katrin ;  Müller, Gerd A. ;  Grosche, Jens ;  Engeland, Kurt

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers