Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 6/29/1998
Publication Date: N/A
Technical Abstract: Previous studies have indicated a fetal loss of approximately 30% in pigs between d 25 and d 50 of pregnancy when fetuses are in a crowded uterine environment. A rapid expansion of the embryonic/fetal blood supply also occurs at this time and may be an important factor in fetal survivability and litter size in pigs. To understand this process, we have cloned a partial cDNA for the porcine (p) erythropoietin receptor (EPOR) and examined the expression of pEPOR mRNA in embryonic/fetal liver on gestational d 24, 30 and 40. Using total RNA from d 30 embryonic pig liver, reverse transcription (RT) followed by polymerase chain reaction (PCR) with primers generated using an EPOR consensus sequence, a partial cDNA of 532 bp (corresponding to a portion of the extracellular domain) for pEPOR was subcloned and sequenced. Additional RT-PCR generated a 867 bp fragment (including most of the cytoplasmic domain). Rapid amplification of cDNA ends (RACE) procedures were used to obtain the 3' end, which was cloned an sequenced, giving a total sequence of 1450 bp, corresponding to amino acids 80-508 of the human EPOR plus the 3' untranslated region. The deduced amino acid sequence shows homology ranging from 79.7% identity with rat EPOR to 89.9% identity with bovine EPOR. Northern analysis indicated an apparent size of 2.3 kb for pEPOR mRNA. Porcine EPOR mRNA was detected in liver (5 ug total RNA) from porcine embryos/fetuses on d 30 and 40 of gestation but not on d 24 (n=3/d). This report is the first known cloning of a partial cDNA for pEPOR. The results indicate a high homology with other known EPOR sequences, and show increased expression of pEPOR mRNA in porcine liver during a time corresponding to a rapid expansion of the erythron and a critical time for fetal survival in a crowded uterine environment.