title: RAPID COMMUNICATION: Expression of an endogenous retroviral element, during early gestation in beef heifers.
abstract: Endogenous retroviral gene elements have been implicated in development and formation of the feto-maternal interface. A variant of the syncytin endogenous retroviral envelope gene family, , was recently found in ruminants. We hypothesized that mRNA would be differentially expressed in utero-placental tissues and would fluctuate during key time points of early gestation in beef heifers. Commercial Angus crossbred heifers ( = 46; ∼15 mo of age; BW = 362.3 ± 34.7kg) housed in 6-animal pens were fed daily with native grass hay and supplemented with cracked corn to gain 0.3 kg/d. The heifers were estrus synchronized, artificially inseminated, (d of breeding= d 0) and ovariohysterectomized on d 16, 22, 28, 34, 40, and 50 ( = 9, 6, 6, 7, 6, and 5, respectively) of gestation and at d 16 of the estrous cycle for non-bred, non-pregnant controls (NP; = 7). Harvested tissues were separated into maternal caruncle (CAR), intercarunclar endometrium (ICAR), and fetal membranes, (FM; chorioallantois, d 22 and later). All tissues were obtained from the ipsilateral uterine horn to the CL. Statistical analyses were conducted via the GLM procedure of SAS. Maternal CAR expression of was greater ( = 0.003) on d 50 by 81.5-fold compared to NP controls. At d 50 expression of in CAR was 190.3-fold greater than ( < 0.0001) ICAR. Fetal membranes had greater ( < 0.002) expression of from d 22 until d 50 of gestation compared to maternal ICAR (d 16 not analyzed). Expression of in FM was greater ( < 0.004) than in CAR until d 40 of gestation. Therefore, we conclude that is differentially expressed in utero-placental tissues and may be involved in the establishment of pregnancy. The expression of in maternal tissues is completely novel and indicates unique functions of syncytin in ruminant pregnancy.
authors.forename: K J
authors.initials: KJ
authors.lastname: McLean
authors.forename: M S
authors.initials: MS
authors.lastname: Crouse
authors.forename: M R
authors.initials: MR
authors.lastname: Crosswhite
authors.forename: D N
authors.initials: DN
authors.lastname: Black
authors.forename: C R
authors.initials: CR
authors.lastname: Dahlen
authors.forename: P P
authors.initials: PP
authors.lastname: Borowicz
authors.forename: L P
authors.initials: LP
authors.lastname: Reynolds
authors.forename: A K
authors.initials: AK
authors.lastname: Ward
authors.forename: B W
authors.initials: BW
authors.lastname: Neville
authors.forename: J S
authors.initials: JS
authors.lastname: Caton
mesh_terms: D000818:Animals; D001947:Breeding; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D019587:Dietary Supplements; D020077:Endogenous Retroviruses; D030762:Estrous Cycle; D004973:Estrus Synchronization; D005260:Female; D015686:Gene Products, env / Q000235:genetics / Q000378:metabolism*; D007315:Insemination, Artificial; D010920:Placenta / Q000502:physiology; D018515:Plant Leaves; D006109:Poaceae; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics / Q000378:metabolism*; D000069466:Red Meat; D012639:Seeds; D003313:Zea mays
chemical_list: D015686:Gene Products, env; D011257:Pregnancy Proteins; C405335:syncytin