Localization of bovine trophoblast protein-1 in the cow blastocyst during implantation: an immunological cryoultrastructural study.
At implantation in ruminants the signal for maintenance of progesterone production by the corpus luteum, essential for a successful pregnancy, is an interferon-like protein (bovine, ovine or caprine trophoblast protein-1; e.g. bTP-1) produced by the blastocyst trophoblast. This quantitative immunogold cryoultrastructural study demonstrates that bTP-1 immunoreactivity is found only in the Golgi complex and associated clear vesicles in the uninucleate trophoblast cells between 18 and 23 days post insemination. The characteristic trophoblast binucleate cells (up to 20 per cent by number) show no significant label at any time. There is also some evidence for transient labelling of the fetomaternal microvillar junction at the time of maximum bTP-1 production suggesting a transfer of the molecule by exocytosis. No evidence for any labelling within the uterine epithelium was observed.
Morgan
G
G
AFRC Institute of Animal Physiology and Genetics Research, Babraham, Cambridge, UK.
Wooding
F B
FB
Godkin
J D
JD
D000818:Animals; D001755:Blastocyst / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D002417:Cattle; D003340:Corpus Luteum Maintenance / Q000502:physiology; D010064:Embryo Implantation / Q000502:physiology*; D005260:Female; D006056:Golgi Apparatus / Q000378:metabolism; D007150:Immunohistochemistry; D007370:Interferon Type I / Q000378:metabolism; D008431:Maternal-Fetal Exchange / Q000502:physiology; D016253:Microscopy, Immunoelectron; D008871:Microvilli / Q000378:metabolism; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000378:metabolism*
D007370:Interferon Type I; D011257:Pregnancy Proteins; C020947:interferon tau