Receptor-Mediated Chicken Oocyte Growth: Differential Expression of Endophilin Isoforms in Developing Follicles1

Receptor-mediated endocytosis of yolk precursors via clathrin-coated structures is the key mechanism underlying rapid chicken oocyte growth. In defining oocyte-specific components of clathrin-mediated events, we have to date identified oocyte-specific yolk transport receptors, but little is known ab...

Full description

Saved in:
Bibliographic Details
Published in:Biology of reproduction 2003-05, Vol.68 (5), p.1850-1860
Main Authors: Hirayama, Satoshi, Bajari, Tarek M, Nimpf, Johannes, Schneider, Wolfgang Johann
Format: Article
Language:English
Subjects:
Contents
follicle
granulosa cells
oocyte development
ovary
theca cells
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Receptor-mediated endocytosis of yolk precursors via clathrin-coated structures is the key mechanism underlying rapid chicken oocyte growth. In defining oocyte-specific components of clathrin-mediated events, we have to date identified oocyte-specific yolk transport receptors, but little is known about the oocytes' supporting endocytic machinery. Important proteins implicated in clathrin-mediated endocytosis and recycling are the endophilins, which thus far have been studied primarily in synaptic vesicle formation; in the present study, as a different highly active endocytic system, we exploit rapidly growing chicken oocytes. Molecular characterization of the chicken endophilins I, II, and III revealed that their mammalian counterparts have been highly conserved. All chicken endophilins interact via their SH3 domain with the avian dynamin and synaptojanin homologues and, thus, share key functional properties of mammalian endophilins. The genes show different expression patterns: As in mammals, expression is low to undetectable in the liver and high in the brain; in ovarian follicles harboring oocytes that are rapidly growing via receptor-mediated endocytosis, levels of endophilins II and III, but not of endophilin I, are high. Immunohistochemical analysis of follicles demonstrated that endophilin II is mainly present in the theca interna but that endophilin III predominates within the oocyte proper. Moreover, in a chicken strain with impaired oocyte growth and absence of egg-laying because of a genetic defect in the receptor for yolk endocytosis, endophilin III is diminished in oocytes, whereas endophilin III levels in the brain and endophilin II localization to theca cells are unaltered. Thus, the present study reveals that the endophilins differentially contribute to oocyte endocytosis and development.
ISSN:0006-3363
1529-7268
DOI:10.1095/biolreprod.102.012427