Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Echinobase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Comp Biochem Physiol C Toxicol Pharmacol 2003 Aug 01;1354:415-24. doi: 10.1016/s1532-0456(03)00143-1.
Show Gene links Show Anatomy links

Calyculin A causes the activation of histone H1 kinase and condensation of chromosomes in unfertilized sea urchin eggs independently of the maturation-promoting factor.

Tosuji H , Fusetani N , Seki Y .

Calyculin A is known to inhibit the type-1 and type-2A phosphatases. We previously reported that calyculin A induces contractile ring formation in unfertilized sea urchin eggs, an increase in histone H(1) kinase activity, and chromosome condensation in the calyculin A-treated unfertilized eggs, and the changes induced by calyculin A are not affected by emetine, an inhibitor of protein synthesis. These observations suggest that the mechanism by which histone H(1) kinases are activated by calyculin A is different from that of maturation-promoting factor (MPF), which is activated by a molecular modification of existed cdc2 and newly synthesized cyclin B. We report here that no cyclin B was detected by immunoblotting of unfertilized calyculin A-treated eggs. In addition, no DNA synthesis was induced by calyculin A. As well, butyrolactone I (an inhibitor of cdc2 and cdk2 kinase) had no effect on the increase in histone H(1) kinase activity nor the chromosome condensation, both of which were induced by calyculin A. Thus, we conclude that calyculin A induces histone H(1) phosphorylation in an MPF-independent manner through inhibition of type-1 phosphatase, and that the chromosome condenses as a result of histone H(1) phosphorylation.

PubMed ID: 12965186
Article link: Comp Biochem Physiol C Toxicol Pharmacol

Genes referenced: cdk2 LOC100887844