Cathepsin L inhibitor I blocks mitotic chromosomes decondensation during cleavage cell cycles of sea urchin embryos

2008 ◽  
Vol 216 (3) ◽  
pp. 790-795 ◽  
Author(s):  
Violeta Morin ◽  
Andrea Sanchez ◽  
Karin Quiñones ◽  
Jenaro Garcia Huidobro ◽  
Claudio Iribarren ◽  
...  
2005 ◽  
Vol 204 (2) ◽  
pp. 693-703 ◽  
Author(s):  
Carolina Concha ◽  
Antonia Monardes ◽  
Yasmine Even ◽  
Violeta Morin ◽  
Marcia Puchi ◽  
...  

Zygote ◽  
1997 ◽  
Vol 5 (2) ◽  
pp. 127-138 ◽  
Author(s):  
Rajnikant Patel ◽  
Elizabeth M. Wright ◽  
Michael Whitaker

SummaryDuring the early mitotic cell cycles of the sea urchin embryo, the cell oscillates between S-phase and M-phase. In the presence of aphidicolin, a DNA synthesis inhibitor, a checkpoint control blocks the activation of the p34cdc2 protein kinase, by keeping it in the inactive, tyrosine phosphorylated form, and the embryos do not enter mitosis. Caffeine has been shown to bypass the G2/M-phase checkpoint in mammalian cells and in cycling Xenopus extracts and to induce mitosis despite the presence of damaged or unreplicated DNA. In this study we show that caffeine also induces mitosis and cell division in sea urchin embryos, in the presence of unreplicated DNA, by stimulating the tyrosine dephosphorylation of p34cdc2 and switching on its protein kinase activity. We also show that the caffeine-induced activation of the p34cdc2 protein kinase is not mediated by either of the two second messengers, calcium and cAMP, or by inhibition of the p34cdc2 tyrosine kinase. Thus, none of the mechanisms proposed for caffeine's action can explain how it overrides the S-phase checkpoint in the early cell cycles of the sea urchin embryo.


Nature ◽  
1988 ◽  
Vol 332 (6162) ◽  
pp. 366-369 ◽  
Author(s):  
Jeremy Twigg ◽  
Rajnikant Patel ◽  
Michael Whitaker

1971 ◽  
Vol 50 (2) ◽  
pp. 516-528 ◽  
Author(s):  
Rudolf A. Raff ◽  
Gerald Greenhouse ◽  
Kenneth W. Gross ◽  
Paul R. Gross

Studies employing colchicine binding, precipitation with vinblastine sulfate, and acrylamide gel electrophoresis confirm earlier proposals that Arbacia punctulata and Lytechinus pictus eggs and embryos contain a store of microtubule proteins. Treatment of 150,000 g supernatants from sea urchin homogenates with vinblastine sulfate precipitates about 5% of the total soluble protein, and 75% of the colchicine-binding activity. Electrophoretic examination of the precipitate reveals two very prominent bands. These have migration rates identical to those of the A and B microtubule proteins of cilia. These proteins can be made radioactive at the 16 cell stage and at hatching by pulse labeling with tritiated amino acids. By labeling for 1 hr with leucine-3H in early cleavage, then culturing embryos in the presence of unlabeled leucine, removal of newly synthesized microtubule proteins from the soluble pool can be demonstrated. Incorporation of labeled amino acids into microtubule proteins is not affected by culturing embryos continuously in 20 µg/ml of actinomycin D. Microtubule proteins appear, therefore, to be synthesized on "maternal" messenger RNA. This provides the first protein encoded by stored or "masked" mRNA in sea urchin embryos to be identified.


2021 ◽  
Vol 172 ◽  
pp. 112922
Author(s):  
Laura DeMiguel-Jiménez ◽  
Nestor Etxebarria ◽  
Xabier Lekube ◽  
Urtzi Izagirre ◽  
Ionan Marigómez

1990 ◽  
Vol 32 (5) ◽  
pp. 489-495 ◽  
Author(s):  
Akiko Fujiwara ◽  
Kenji Kataoka ◽  
Kaori Mikami-Takei ◽  
Eigoro Tazawa ◽  
Ikuo Yasumasu

Sign in / Sign up

Export Citation Format

Share Document