Nuclear assembly of demembranated Xenopus sperm in plant cell-free extracts from Nicotiana ovules.
The cell-free preparation derived from Nicotiana tabaccum ovules induced chromatin decondensation and pronuclear formation from demembranated Xenopus laevis sperm nuclei. Fluorescent microscope and phase-contrast microscope visualization of assembly intermediates indicated that 95.6% of X. leavis sperm changed their tadpole-like shape to circular shape or elliptical shape after over 1.5 h of incubation. Transmission electron microscope visualization showed that nuclear membrane was assembled around the periphery of the dispersed chromatin. Nuclear envelope of most reassembled nuclei was composed of a double membrane inlaid with a little single membrane. Nucleosome assembly was verified by means of micrococcal nuclease digestion. After 2 to 5 h of incubation, digestion of the product of nuclear assembly with micrococcal nuclease produced at least six nucleosome fragments of about 250 bp each.
Lu
P
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School of Life Sciences, Peking University, Beijing, 100871, China. luping@pku.edu.cn
Zhai
Z H
ZH
D000818:Animals; D002457:Cell Extracts; D002462:Cell Membrane; D002467:Cell Nucleus / Q000502:physiology*; D002474:Cell-Free System; D002843:Chromatin / Q000502:physiology*; D008297:Male; D009707:Nucleosomes / Q000502:physiology; D013094:Spermatozoa / Q000502:physiology* / Q000648:ultrastructure; D013997:Time Factors; D014026:Nicotiana / Q000378:metabolism; D014982:Xenopus laevis
D002457:Cell Extracts; D002843:Chromatin; D009707:Nucleosomes