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  current news   Press   selected story    
     
  24th August 2012  
  Evolution of the Cdk-activator Speedy/RINGO in vertebrates
 
 




Authors
Sangeeta Chauhan1, Xinde Zheng1, Yue Ying Tan2, Boon-Hui Tay2, Shuhui Lim1, Byrappa Venkatesh2,*, Philipp Kaldis1,*

1 - Cell Division and Cancer Research Lab
2 - Comparative Genomics Lab
*   Corresponding authors

The Kaldis laboratory has been working on Speedy proteins, which bind to and activate cyclin-dependent kinases (Cdks). In the mouse there are several Speedy genes but not all of them have homologs in humans. In order to learn more about the origin, evolution, diversity and functions Speedy proteins, a close collaboration with the Venkatesh laboratory was started. With equal contribution from both IMCB laboratories, we were able to complete a full analysis and submit a comprehensive manuscript for publication.

Published online in Cellular and Molecular Life Sciences on 5th July 2012.

Abstract
Successful completion of the cell cycle relies on the precise activation and inactivation of cyclin dependent kinases (Cdks) whose activity is mainly regulated by binding to cyclins. Recently, a new family of Cdk regulators termed Speedy/RINGO has been discovered, which can bind and activate Cdks but shares no apparent amino acid sequence homology with cyclins. All Speedy proteins share a conserved domain of approximately 140 amino acids called "Speedy Box", which is essential for Cdk binding. Speedy/RINGO proteins display an important role in oocyte maturation in Xenopus. Interestingly, a common feature of all Speedy genes is their predominant expression in testis suggesting that meiotic functions may be the most important physiological feature of Speedy genes. Speedy homologs have been reported in mammals and can be traced back to the most primitive clade of chordates (Ciona intestinalis). Here, we investigated the evolution of the Speedy genes and have identified a number of new Speedy/RINGO proteins. Through extensive analysis of numerous species, we discovered diverse evolutionary histories: the number of Speedy genes varies considerably among species, with evidence of substantial gains and losses. Despite the interspecies variation, Speedy is conserved among most species examined. Our results provide a complete picture of the Speedy gene family and its evolution.

Figure Legend: Phylogenetic relationship of the Speedy protein family.
Neighbor-joining phylogenetic tree displaying the evolutionary relationship of Speedy proteins based on their amino acid sequences. The amphioxus Speedy sequence was used as an out-group to root the tree. Numbers represent bootstrap values (given as percentages) for a particular node

For more information on Philipp KALDIS's laboratory, please click here.

For more information on Byrappa VENKATESH's laboratory, please click here.