Frog eggs

Hunt There is another complication here it turns out that the cyclin A in CSF-arrested frog eggs is extremely unstable. The APC is certainly active in that situation, and the checkpoint that prevents the degradation of B-type cyclins can somehow recognize and spare the cyclin B, but has no effect on cyclin A. 

Gurdon IB, Lane CD, Woodland HR, Marbaix G. 1971. Use of frog eggs and oocytes for the study of messenger RNA and its translation in living cells. Nature. 233 177. 

John Gurdon, a British biologist, pursued the next question Can a differentiated cell from the intestine of a frog egg dedifferentiate and then redifferentiate into an adult frog The result demonstrated in 1966 that the... 

Organelles, such as nuclei, endoplasmic reticulum (ER), and Golgi, can be assembled in cell-free extracts. Extracts made from frog eggs (see Fig. 5) (Lohka and Masui, 1984) are a particularly powerful system for studying the assembly, dynamics, and functions of these organelles (see also chapter by Lohka and Warren, this volume). Organelles can be isolated cleanly from the extract and... 

The assembly of the NPC is a particularly challenging problem. The assembly of NPCs occurs in asynchronous fashion on the chromatin surface in both intact cells and in cell-free extracts. In frog egg extracts it is not uncommon to see patches of apparently fully assembled NE, complete with NPCs, at some sites on the chromatin surface, whereas at other sites vesicles have not yet bound or are just beginning to bind and fuse with each other (Lohka and Masui, 1983, 1984). In the absence of a system where NPCs are assembled in a synchronous manner, it will be difficult to capture assembly intermediates of NPCs for molecular analysis. As a consequence of this problem, the events that precede and follow the fusion of the inner and outer NE membranes remain elusive. Although... 

Figure 28.9 For the maturation of frog eggs, the production of phosphorylated mitogen-activated protein kinase (MAPK-P) is governed by small changes in the concentration of the MOS protein. This relationship can be described by the Hill model. Source JE Ferrel and EM Machleder, Science 280, 895-898 (1998). 

Briggs, R. and King, T. J. 1952. Transplantation of hving nuclei from blastula cells into enucleated frogs eggs. Proc Natl Acad Sci USA 38(5) 455-63. 

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