Cloning of Rous sarcoma virus enhancer factor genes. II. RSV-EF-II, abundantly expressed in fibroblasts and muscle tissue, binds to an octamer sequence, 5'-GTACCACC-3', in the noncoding strand of RSV enhancer.
Cloning of Rous sarcoma virus enhancer factor genes. II. RSV-EF-II, abundantly expressed in fibroblasts and muscle tissue, binds to an octamer sequence, 5'-GTACCACC-3', in the noncoding strand of RSV enhancer.
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劳斯肉瘤病毒增强因子基因的克隆。
DOI：
10.1006/viro.1996.0404
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Guntaka,RV
中科院分区：
文献类型：
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作者：
Cleavinger,PJ;Shin,BA;Kandala,JC;Nambiar,A;Swamynathan,SK;Guntaka,RV
劳斯肉瘤病毒（RSV）主要在禽类成纤维细胞中复制，其长末端重复序列的U3增强子区含有其组织嗜性表达的决定因子。我们描述了一个禽类基因的克隆和鉴定，该基因编码能够与劳斯肉瘤病毒增强子区域结合的蛋白质。用PCR扩增的RSV U3区探针筛选鸡的cDNA表达文库，分离出一个cDNA克隆。预测cDNA编码298个氨基酸的多肽，其与DNA结合转录因子的Y盒（反向CCAAT）家族同源。这个因子，我们称之为劳斯肉瘤病毒增强因子-II（RSV-EF-II），在所有Y盒蛋白中高度保守的105个氨基酸序列上显示出99%的氨基酸同一性，通常被称为冷休克结构域。RSV-EF-II选择性结合单链DNA，通过电泳迁移率变动试验确定，结合位点由位于RSV增强子非编码链中核苷酸− 112至− 119之间的序列5 ′ GTACCACC 3 ′组成。尽管RSV-EF-II与Y盒蛋白家族有相当大的同源性，但它不与RSV LTR中− 65至− 69和− 129至− 133位的反向CCAAT盒结合。北方分析表明RSV-EF-II特异性转录物主要在禽类成纤维细胞和肌肉组织中表达。这些结合和mRNA表达实验的结果表明，RSV-EF-II可能在RSV LTR驱动的基因表达的组织和宿主特异性表达中发挥重要作用。此外，我们表明，RSV-EF-II作为一个转录的阻遏物。
Rous sarcoma virus (RSV) mainly replicates in avian fibroblasts, and the U3 enhancer region of the long terminal repeats of RSV contains the determinants for its tissue-tropic expression. We describe the cloning and characterization of an avian gene that encodes a protein capable of binding to the enhancer region of Rous sarcoma virus. A PCR-derived probe corresponding to the U3 region of RSV was used to isolate a cDNA clone by screening a chicken cDNA expression library. The cDNA is predicted to encode a polypeptide of 298 amino acids that is homologous to the Y-box (inverted CCAAT) family of DNA-binding transcription factors. This factor, which we refer to as Rous sarcoma virus enhancer factor-II (RSV-EF-II), shows 99% aa identity over a 105-amino-acid stretch that is highly conserved in all Y-box proteins, and is commonly referred to as the cold shock domain. RSV-EF-II selectively binds to single-stranded DNA, and the binding site, as determined by electrophoretic mobility shift assays, consists of the sequence 5′ GTACCACC 3′ located between nucleotides −112 to −119 in the noncoding strand of the RSV enhancer. Although RSV-EF-II shares considerable homology with the Y-box family of proteins, it does not bind to the inverted CCAAT boxes at positions −65 to −69 and −129 to −133 in the RSV LTR. Northern analysis indicates that RSV-EF-II-specific transcripts are expressed predominantly in avian fibroblasts and muscle tissue. The results of these binding and mRNA expression experiments suggest that RSV-EF-II may play an important role in tissue- and host-specific expression of RSV LTR-driven gene expression. Further, we show that RSV-EF-II acts as a repressor of transcription.