Systematic Bioinformatic Analysis Of Cyclins

Cyclins is one of the most important regulatory factors in cell division.The activity of CDK is directly regulated by binding and activation of cyclins in the cell cycle.Many researches revealed that cyclin contained a conserved region called the cyclin core of approximately250amino acids in length, which consisted of two domains:cyclin_N and cyclin_C.Our research was performed by using the GeneBank as our database，retrieving365cyclins in ten model species for the basic data,and these365cyclins was classified by cyclin domain characteristics. We emphatically analyzed two classes of integrated double cyclin box cyclins and integrated single cyclin box cyclins, and then analysed some special cyclins on the phylogenetic tree that we constucted.Finally we carryed out these conclusions as follows:1. Higher organisms shared more cyclins on numbers and types which also suggested higher organisms carryed out more complicated control mechanisms of the cell cycle.Compared with plants.fungi and prokaryotes.animals possessed more cyclin types,but the majority of these types in plants encompassed more members than those in animals.2. Cyclin C is an important domain which may determine some cyclins’functions in cell cycle.3. G2/M phase cyclins contained cyclin core while most G1/S phase cyclins just contained a single cyclin box in unicellular eukaryotic organisms. Cyclins in prokaryotic cell and unicellular eukaryotic cell shared high sequence similarity.4. Some cyclins from different species and different families may play a similar role in their cell cycle,such as the cyclin U/P in plants and cyclin Y in animals;some cyclins may funtion as another cyclins which lacking in this species.For example,no cyclin E have been found in plants so far.so someother cyclins may function be analogous to cyclin E in animals.5. The evolutionary trends of eukaryotic cyclins was increasing their numbers and types, and the evolutionary difference between animals and plants showed that animals mainly increased types of cyclins, whereas plants increased members of each cyclin type. Another evolutionary trends of eukaryotic cyclins was duplicating cyclin box domain, and the higher evolutionary of the species, the more types of cyclins with double cyclin box domain they had.