Interferon RNA of embryonic origin is expressed transiently during early pregnancy in the ewe.
Ovine trophoblast protein-1 (oTP-1), an interferon of embryonic origin, is produced during the peri-implantation period of early pregnancy. Secretion of oTP-1 is detectable between days 13 and 21, but not beyond. In this study, the levels of oTP-1 mRNA in embryos were analyzed to determine if they reflected the transient nature of oTP-1 production. Total cellular RNA (tcRNA) was isolated from embryos representing day 12 (n = 5), 14 (n = 7), 16 (n = 5), 18 (n = 6), 20 (n = 4), and 22 (n = 5) of pregnancy and spotted on nylon membranes. Complementary RNA was transcribed from a specific oTP-1 cDNA (550 base pairs) template and applied (16-1000 pg) to nylon membranes to develop a standard curve. The fixed RNA samples were then allowed to hybridize with the 32P-labeled oTP-1 cDNA. oTP-1 mRNA was not detectable on day 12, increased to high levels (3.6 +/- 1.6 ng/ug of embryo DNA) on day 14, decreased about 5-fold by day 16, 15-fold by day 18, 170-fold by day 20, and 200-fold by day 22 of pregnancy. At day 14 oTP-1 mRNA comprised 0.060 +/- 0.019% of the tcRNA and was more abundant than actin mRNA. Northern analyses of pooled tcRNA representing each day of pregnancy showed that the oTP-1 probe hybridized to a single class of mRNA (approximately 1.1 kilobases) and confirmed the results obtained with dot blots.
Hansen
T R
TR
Department of Animal Science, University of Missouri, Columbia 65211.
Imakawa
K
K
Polites
H G
HG
Marotti
K R
KR
Anthony
R V
RV
Roberts
R M
RM
D000199:Actins / Q000235:genetics; D000818:Animals; D005260:Female; D007370:Interferon Type I; D007372:Interferons / Q000235:genetics*; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics; D012313:RNA / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis; D012756:Sheep
D000199:Actins; D007370:Interferon Type I; D011257:Pregnancy Proteins; D012333:RNA, Messenger; C020947:interferon tau; D012313:RNA; D007372:Interferons