Serosa membrane plays a key role in transferring vitellin polypeptides to the perivitelline fluid in insect embryos.
Dev Growth Differ
; 43(6): 725-33, 2001 Dec.
Article
em En
| MEDLINE
| ID: mdl-11737153
ABSTRACT
In mid-embryogenesis, the stick insect Carausius morosus comes to be comprised of three distinct districts the embryo proper, the yolk sac and the perivitelline fluid. A monolayered epithelium, the so-called serosa membrane, encloses the yolk sac and its content of vitellophages and large yolk granules. During embryonic development, the yolk sac declines gradually in protein concentration due to Vt polypeptides undergoing limited proteolysis to yield a number of Vt cleavage products of lower molecular weights. mAbs 1D1 and 5H11 are monoclonal antibodies raised against some of the Vt cleavage products generated by this process in the yolk sac. At the confocal microscope, antibody fluorescence is initially associated with a few yolk granules, while it is gradually displaced in the cytosolic spaces of the vitellophages. With the proceeding of embryonic development, label appears also in the serosa membrane in the form of clustered dots. At the ultrastructural level, gold particles are initially associated with the vitellophages that are labeled on a few yolk granules and in the cytosolic space flanking the yolk granules. Subsequently, the serosa cells become labeled on vesicles close to the yolk granules or just underneath the plasma membrane. Inside the serosa cells, label is also associated with granules budding from the Golgi apparatus, but never with the intercellular channels percolating the serosa membrane. These observations are interpreted as indicating that Vt cleavage products leak out from the yolk granules into the cytosolic spaces of the vitellophages and are eventually transferred to the perivitelline fluid via transcytosis through the serosa cells.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas do Ovo
/
Insetos
Limite:
Animals
Idioma:
En
Ano de publicação:
2001
Tipo de documento:
Article