Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1992-2-25
pubmed:abstractText
Following fertilization, the Xenopus egg cortex rotates relative to the cytoplasm by 30 degrees about a horizontal axis. The direction of rotation, and as a result the orientation of the embryonic body axes, is normally specified by the position of sperm entry. The mechanism of rotation appears to involve an array of aligned microtubules in the vegetal cortex (Elinson and Rowning, 1988, Devl Biol. 128, 185-197). We performed anti-tubulin immunofluorescence on sections to follow the formation of this array. Microtubules disappear rapidly from the egg following fertilization, and reappear first in the sperm aster. Surprisingly, astral microtubules then extend radially through both the animal and vegetal cytoplasm. The cortical array arises as they reach the vegetal cell surface. The eccentric position of the sperm aster gives asymmetry to the formation of the array and may explain its alignment since microtubules reaching the cortex tend to bend away from the sperm entry side. The radial polymerization of cytoplasmic microtubules is not dependent on the sperm aster or on the female pronucleus: similar but more symmetric patterns arise in artificially activated and enucleate eggs, slightly later than in fertilized eggs. These observations suggest that the cortical microtubule array forms as a result of asymmetric microtubule growth outward from cytoplasm to cortex and, since cortical and cytoplasmic microtubules remain connected throughout the period of the rotation, that the microtubules of the array rotate with the cytoplasm.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0950-1991
pubmed:author
pubmed:issnType
Print
pubmed:volume
112
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
107-17
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Patterns of microtubule polymerization relating to cortical rotation in Xenopus laevis eggs.
pubmed:affiliation
Department of Zoology, University of Toronto, Ontario, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't