Gifford C A, Assiri A M, Satterfield M C, Spencer T E, Ott T L
Department of Animal and Veterinary Science, University of Idaho, Moscow, Idaho 83843, USA.
Biol Reprod. 2008 Sep;79(3):518-24. doi: 10.1095/biolreprod.108.069468. Epub 2008 May 21.
Interferon-tau (IFNT) is secreted by the conceptus trophoblast and signals pregnancy recognition in ruminants. IFNT regulates expression of genes in the endometrium, peripheral blood leukocytes (PBLs), and corpus luteum (CL). Microarray analysis identified that expression of (chemosensory) receptor transporter protein 4 (RTP4) increased in PBLs during early pregnancy in cows. In the present study, we cloned and characterized RTP4 transcription during early pregnancy in ewes. Endometrium, PBLs, and CL were collected on Days 11, 13, and 15 of the cycle and on Days 11, 13, 15, 17, and 19 of pregnancy. Northern blot analysis revealed an expected 1.6-kb mRNA and an unexpected 2.6-kb mRNA. In endometria, RTP4 mRNA levels in cyclic ewes remained low, whereas RTP4 mRNA increased from Day 11 to Day 17 in pregnant ewes. Levels of RTP4 mRNA also increased from Day 15 to Day 19 in CL and PBL samples from pregnant ewes only. The RTP4 mRNA was located in the glandular epithelium, stratum compactum, and caruncular stroma. Ovine glandular epithelial cells were treated with IFNT to determine if IFNT alone could induce RTP4. IFNT increased RTP4 more than 70-fold at 1.5 h after treatment, with maximal induction of nearly 300-fold above values observed in nontreated controls at 6 h after treatment. These results indicate that RTP4 mRNA levels are induced in the ovine endometrium, PBLs, and CL by IFNT during early pregnancy and in cell culture in response to IFNT. If RTP4 expression affects G protein-coupled receptor function, it may be important for establishment of pregnancy in domestic ruminants.
干扰素 - τ（IFNT）由孕体滋养层分泌，是反刍动物妊娠识别的信号分子。IFNT可调节子宫内膜、外周血白细胞（PBL）和黄体（CL）中基因的表达。微阵列分析表明，奶牛妊娠早期外周血白细胞中（化学感应）受体转运蛋白4（RTP4）的表达增加。在本研究中，我们克隆并鉴定了母羊妊娠早期RTP4的转录情况。在发情周期的第11、13和15天以及妊娠的第11、13、15、17和19天采集子宫内膜、外周血白细胞和黄体。Northern印迹分析显示预期的1.6 kb mRNA和意外的2.6 kb mRNA。在子宫内膜中，发情周期母羊的RTP4 mRNA水平保持较低，而妊娠母羊中RTP4 mRNA从第11天到第17天增加。仅在妊娠母羊的黄体和外周血白细胞样本中，RTP4 mRNA水平也从第15天到第19天增加。RTP4 mRNA位于腺上皮、致密层和肉阜基质中。用IFNT处理绵羊腺上皮细胞，以确定单独的IFNT是否能诱导RTP4。IFNT处理后1.5小时，RTP4增加超过70倍，处理后6小时最大诱导倍数比未处理对照高出近300倍。这些结果表明，在妊娠早期，IFNT可诱导绵羊子宫内膜、外周血白细胞和黄体中RTP4 mRNA水平升高，且在细胞培养中IFNT也可诱导其升高。如果RTP4的表达影响G蛋白偶联受体功能，那么它可能对家畜反刍动物的妊娠建立很重要。
