The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 
 
 

Molecular cloning and immunological analysis of goldfish cyclin A during oocyte maturation.

Cyclin A belongs to a family of proteins involved in the regulation of the eukaryotic cell cycle. Although cyclin A is thought to be involved in the regulation of both S and M phase, its exact role in the cell cycle, especially in the meiotic cycle (oocyte maturation), is uncertain. We isolated cyclin A cDNA clones from a goldfish oocyte cDNA library. Monoclonal antibody raised against bacterially produced goldfish cyclin A recognized a 47-kDa protein that disappeared after egg activation. Unlike goldfish cyclin B, which is absent in immature oocytes, cyclin A was already present in immature oocytes and its protein level did not change remarkably during oocyte maturation. These results differ from the finding in Xenopus, in which cyclin A is absent, but cyclin B is present, in immature oocytes. Goldfish cyclin A was associated with cdc2 kinase in mature oocytes, but not with cdk2. Recombinant cyclin A bound to and activated cdc2 in a cell-free system, but cyclin A and cdk2 binding was not observed. The kinase activity of cyclin A-cdc2 was undetectable in immature oocytes and first appeared at about the time of germinal vesicle breakdown (GVBD). In contrast to the cyclin B-cdc2 activity that corresponded to the occurrence of GVBD, cyclin A-cdc2 activity increased only slightly until GVBD was completed and increased drastically after the completion of the first meiotic division. Furthermore, microinjection of cyclin A mRNA into immature oocytes did not cause GVBD; however, microinjection of cyclin B mRNA did. These results suggest that cyclin A-cdc2 kinase and cyclin B-cdc2 kinase play different roles in controlling oocyte maturation. The roles of cyclin A in the rapid activation of cyclin B-cdc2 kinase at meiosis I and II transition and in the maintenance of high maturation-promoting factor activity in mature unfertilized eggs are discussed.[1]

References

  1. Molecular cloning and immunological analysis of goldfish cyclin A during oocyte maturation. Katsu, Y., Yamashita, M., Hirai, T., Tokumoto, T., Kajiura, H., Nagahama, Y. Dev. Biol. (1995) [Pubmed]
 
WikiGenes - Universities