Linked Life Data

1638982

Source:http://linkedlifedata.com/resource/pubmed/id/1638982

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1992-8-31
pubmed:abstractText
The unfertilized ascidian egg displays a visible polar organization along its animal-vegetal axis. In particular, the myoplasm, a mitochondria-rich subcortical domain inherited by the blastomeres that differentiate into muscle cells, is mainly situated in the vegetal hemisphere. We show that, in the unfertilized egg, this vegetal domain is enriched in actin and microfilaments and excludes microtubules. This polar distribution of microfilaments and microtubules persists in isolated cortices prepared by shearing eggs attached to a polylysine-coated surface. The isolated cortex is further characterized by an elaborate network of tubules and sheets of endoplasmic reticulum (ER). This cortical ER network is tethered to the plasma membrane at discrete sites, is covered with ribosomes and contains a calsequestrin-like protein. Interestingly, this ER network is distributed in a polar fashion along the animal-vegetal axis of the egg: regions with a dense network consisting mainly of sheets or tightly knit tubes are present in the vegetal hemisphere only, whereas areas characterized by a sparse tubular ER network are uniquely found in the animal hemisphere region. The stability of the polar organization of the cortex was studied by perturbing the distribution of organelles in the egg and depolymerizing microfilaments and microtubules. The polar organization of the cortical ER network persists after treatment of eggs with nocodazole, but is disrupted by treatment with cytochalasin B. In addition, we show that centrifugal forces that displace the cytoplasmic organelles do not alter the appearance and polar organization of the isolated egg cortex. These findings taken together with our previous work suggest that the intrinsic polar distribution of cortical membranous and cytoskeletal components along the animal-vegetal axis of the egg are important for the spatial organization of calcium-dependent events and their developmental consequences.
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
115
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
221-37
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Polarity of the ascidian egg cortex before fertilization.
pubmed:affiliation
Unité de Biologie Cellulaire Marine, URA 671 CNRS/Université Paris VI, Villefranche-sur-Mer, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't