Differential distribution of mRNA for the alpha- and beta-subunits of chorionic gonadotrophin in the implantation stage blastocyst of the marmoset monkey.
We studied the expression of mRNA encoding the alpha- and beta-subunits of marmoset chorionic gonadotrophin (mCG) in implantation stage blastocysts and in a trophoblastic cell line derived from such blastocysts. In this investigation in situ hybridization was carried out using digoxygenin-labelled riboprobes to localize the subunit transcripts. The trophoblastic cell line, known to secrete bioactive mCG, was used as a positive control. Marmoset uterine embryos were cultured to hatched blastocysts and following growth on Matrigel or plastic were processed for in situ hybridization at developmental stages ranging from 13-15 days post-conception. In serial sections mCG-beta mRNA was detected mainly in polar trophoblast. The mRNA for mCG-alpha was expressed more uniformly in polar and mural trophoblast. Transcripts for the beta-subunit were not expressed, or present as weak signals, in the inner cell mass (ICM) and endoderm. However, low levels of mRNA for mCG-alpha were detected in the ICM and visceral endoderm. We have concluded that mRNA for mCG-beta was primarily localized to patches of syncytiotrophoblast at the embryonic pole and sparsely distributed in mural trophoblast, while the transcripts for mCG-alpha were distributed more uniformly in differentiating cytotrophoblast and syncytium, and at much lower levels in ICM and early endoderm.
Lopata
A
A
Department of Obstetrics and Gynaecology, University of Melbourne, Royal Women's Hospital, Carlton, Victoria.
Berka
J
J
Simula
A
A
Norman
R
R
Otani
T
T
D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000378:metabolism*; D002144:Callithrix; D002460:Cell Line; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000096:biosynthesis* / Q000235:genetics; D010064:Embryo Implantation / Q000502:physiology*; D005314:Embryonic and Fetal Development; D005260:Female; D017403:In Situ Hybridization; D008297:Male; D011247:Pregnancy; D015347:RNA Probes; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D014158:Transcription, Genetic; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism*
D006063:Chorionic Gonadotropin; D015347:RNA Probes; D012333:RNA, Messenger