Article

The germinal vesicle material required for sperm pronuclear formation is located in the soluble fraction of egg cytoplasm.

Experimental Cell Research (impact factor: 3.58). 11/1983; 148(2):481-91. pp.481-91
Source: PubMed

ABSTRACT The chromatin of Xenopus laevis sperm nuclei was induced to decondense, swell and form mitotic chromosomes following its injection into mature Rana pipiens oocytes. In contrast, the sperm chromatin did not decondense or form mitotic chromosomes when injected into oocytes from which the germinal vesicle (GV) was removed prior to the initiation of maturation. Injection into enucleated oocytes of the material extracted from manually-isolated GVs restored their ability to decondense sperm nuclei. This soluble GV material was stable at 18 degrees C for 16 h but was inactivated by heating to 80 degrees C for 10 min. We examined the distribution of this GV material in a cytoplasmic preparation from activated eggs which can induce sperm pronuclear formation in vitro. The cytoplasmic preparation was separated into soluble and particulate fractions by centrifugation and then each fraction was injected into enucleated eggs to determine whether or not it restored the ability to decondense sperm nuclei. We found that the soluble, but not the particulate fraction could restore the ability to decondense sperm nuclei to enucleated oocytes. This result clearly indicates that the soluble fraction contains most of the GV material required for chromatin decondensation. However, since the soluble fraction fails to decondense sperm chromatin in vitro in the absence of material from the particulate fraction, sperm pronuclear formation appears to require both the soluble material derived from the GV and particulate material which can develop in the oocyte cytoplasm in the absence of the GV.

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Keywords

18 degrees C
 
80 degrees C
 
chromatin decondensation
 
decondense sperm chromatin
 
decondense sperm nuclei
 
enucleated oocytes
 
form mitotic chromosomes
 
germinal vesicle
 
GV material
 
inactivated
 
mature Rana pipiens oocytes
 
particulate fraction
 
particulate fractions
 
particulate material
 
soluble fraction
 
soluble GV material
 
soluble material
 
sperm chromatin
 
sperm pronuclear formation
 
Xenopus laevis sperm nuclei
 

M J Lohka