Gene Networks Database

Strongylocentrotus purpuratus Genes in Development: Cyclin

Cyclin B


Cyclin B is a key regulatory protein of the cell cycle, central to the control of the G2/M transition. The mitotic cyclins or B-type cyclins are involved in regulating the events of mitosis and are necessary for movement from G2 through M. Cyclin B associates with the cdc2 kinase in early G2 to form a complex which, after a series of controlled phosphorylations and dephosphorylations, becomes activated (Thatcher et al., 1995).


Subcellular location

Expression Pattern

Cyclin B appears to be zygotically activated around 8 hr post fertilization. In situ hybridization data indicate that the abundance of cyclin mRNA transcripts parallels the pattern of cell divisions in a manner similar to that found in Drosophila embryos (Kingsley et al., 1992). Spatial distribution of cyclin B mRNA transcripts is uniform in early development. These transcripts become enriched in or restricted to the oral ectoderm and endoderm (tissues that contain significant numbers of dividing cells). At the same time, cyclin B transcripts are down-regulated in the aboral ectoderm (Masuda and Sato, 1984).



Regulatory Regions

5` regulatory region

Regulatory Connections

Upstream Genes

Cyclin B

Downstream Genes

Evolutionary Homologues


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