Different ovine interferon-tau genes are not expressed identically and their protein products display different activities.
Different ovine interferon-tau genes are not expressed identically and their protein products display different activities.
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不同的绵羊干扰素tau基因的表达并不相同，其蛋白质产物表现出不同的活性。
DOI：
10.1095/biolreprod58.2.566
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发表时间：
1998
影响因子：
3.6
通讯作者：
Roberts,RM
中科院分区：
文献类型：
--
作者：
Ealy,AD;Green,JA;Alexenko,AP;Keisler,DH;Roberts,RM
干扰素τ（IFN-τ）蛋白在滋养层与子宫上皮最终附着之前由绵羊孕体分泌几天，并起到延长黄体寿命的作用。绵羊中有多个基因编码IFN-τ，但目前尚不清楚哪些基因在妊娠早期表达，以及这些基因编码的蛋白质是否等效。研究了三种不同的绵羊（ov）IFN-τ基因变体p3、p6和s4，以确定它们在基因表达方面是否不同以及蛋白质是否显示出不同的生物活性。通过使用RNase保护试验，在妊娠第12-13天、第15-16天和第18-19天从子宫冲洗出来的孕体中检测到p3和p6的全长保护片段的比例大致相似，但全长保护的s4转录物的量为p3和p6的10%至20%。部分受保护的探针片段也很明显，可能来自探针与相关ovIFN-τ转录物的杂交。当在Madin-Darby牛肾细胞上测试时，产生的重组蛋白质显示出34.2（p3）、8.4（p6）和11.9（s4）单位（× 10（-7））的活性/mg蛋白质。对人Daudi细胞的抗增殖活性在干扰素之间变化很大，p3比s4有效2000倍。在发情后10 ~ 18天将干扰素注射到母羊子宫腔内。与对照组（15.8 ± 0.6天）相比，300 µg/天p3（31.7 ± 7.8天）或300 µg/天p6（25.5 ± 4.2天）时黄体（CL）的功能寿命延长（p = 0.02），但300 µg/天s4（19.2 ± 2.9天）时未延长。然而，注射1 mg/天s4确实延长了（p = 0.02）CL寿命（23.5 ± 4.1天）。这些数据表明，IFN-τ基因在滋养外胚层中的表达并不相等，ovIFN-τ基因编码的蛋白质具有显著不同的生物学效力。
Interferon τ (IFN-τ) proteins are secreted by the ovine conceptus for a few days before definitive attachment of the trophoblast to the uterine epithelium and act to prolong luteal life span. Multiple genes encode for IFN-τ in sheep, but it remains unclear which genes are expressed during early pregnancy and whether the proteins encoded by these genes are equipotent. Three distinct ovine (ov) IFN-τ gene variants, p3, p6, and s4, were examined to determine whether they differed in gene expression and whether the proteins displayed different biological activities. By using RNase protection assays, full-length protected fragments were detected for p3 and p6 in approximately similar proportions in conceptuses flushed from the uterus at Days 12-13, Days 15-16, and Days 18-19 of pregnancy, but the amount of full-length protected s4 transcripts was 10% to 20% of that for p3 and p6. Partially protected probe fragments were also evident, presumably from probe hybridization to related ovIFN-τ transcripts. Recombinant proteins were generated and exhibited 34.2 (p3), 8.4 (p6), and 11.9 (s4) units (× 10(-7)) of activity per milligram of protein when tested on Madin-Darby bovine kidney cells. Antiproliferative activity on human Daudi cells varied considerably between the interferons, with p3 being 2000-fold more potent than s4. The interferons were injected into the uterine lumen of ewes from 10 to 18 days postestrus. The functional life span of the corpus luteum (CL) was increased (p = 0.02) by either 300 µg/day p3 (31.7 ± 7.8 days) or 300 µg/day p6 (25.5 ± 4.2 days), but not by 300 µg/day s4 (19.2 ± 2.9 days), when compared to controls (15.8 ± 0.6 days). Injection of 1 mg/day s4 did, however, increase (p = 0.02) CL life span (23.5 ± 4.1 days). These data suggest that IFN-τ genes are not equally expressed in trophectoderm and that ovIFN-τ genes encode for proteins with significantly different biological potency.