INVITRO BINDING OF HUMAN T-CELL LEUKEMIA-VIRUS REX PROTEINS TO THE REX-RESPONSE ELEMENT OF VIRAL TRANSCRIPTS
INVITRO BINDING OF HUMAN T-CELL LEUKEMIA-VIRUS REX PROTEINS TO THE REX-RESPONSE ELEMENT OF VIRAL TRANSCRIPTS
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DOI：
10.1128/jvi.65.7.3721-3727.1991
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发表时间：
1991-07-01
影响因子：
5.4
通讯作者：
FLECKENSTEIN, B
中科院分区：
文献类型：
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作者：
GRASSMANN, R;BERCHTOLD, S;FLECKENSTEIN, B
人T细胞白血病病毒（HTLV-1，HTLV-Ⅱ）雷克斯蛋白功能是编码结构蛋白的不完全剪接病毒转录物的胞质表达所必需的。 该效应由位于所有病毒mRNA的3'端附近的顺式作用的Rex反应元件（RRX）介导。 我们表明，雷克斯多肽的HTLV-I和HTLV-II在大肠杆菌中表达的能够特异性结合RRX的转录的两种病毒在无细胞测定。 与雷克斯蛋白的缺失变体的结合分析揭示了在前77个N-末端氨基酸中具有RNA结合活性的结构域。 从N末端去除19个氨基酸的碱性肽废除了RNA结合，而含有该肽的β-半乳糖苷酶融合蛋白与RRX结合。 这些结果表明，直接结合的雷克斯蛋白的RRX是重要的雷克斯介导的调节病毒基因的表达和一小段带正电荷的氨基酸有助于特异性结合的雷克斯其靶RNA。
Human T-cell leukemia virus (HTLV-I, HTLV-II) rex protein function is required for the cytoplasmic expression of incompletely spliced viral transcripts encoding structural proteins. The effect is mediated by a cis-acting rex-response element (RRX) which is located near the 3' end of all viral mRNAs. We show that rex polypeptides of HTLV-I and HTLV-II expressed in Escherichia coli are capable of specifically binding RRX-containing transcripts of both viruses in cell-free assays. Binding analyses with deletion variants of rex proteins revealed a domain with RNA-binding activity in the first 77 N-terminal amino acids. Removal of a basic peptide of 19 amino acids from the N terminus abrogated RNA binding, whereas a beta-galactosidase fusion protein containing this peptide bound to the RRX. These results suggest that direct binding of rex protein to the RRX is important for rex-mediated regulation of viral gene expression and that a short stretch of positively charged amino acids contributes to the specific binding of rex to its target RNA.