Bugert J J, Lohmüller C, Damon I, Moss B, Darai G
Institut für Medizinische Virologie der Ruprecht-Karls-Universität Heidelberg, Federal Republic of Germany.
Virology. 1998 Mar 1;242(1):51-9. doi: 10.1006/viro.1997.9001.
An analysis of the complete Molluscum contagiosum virus (MCV-1) genome sequence revealed a 104-amino-acid open reading frame (MC148R) that is structurally related to the beta (CC) family of chemokines. The predicted MCV chemokine homolog (MCCH) has a deletion in the NH2-terminal activation domain, suggesting the absence of chemoattractant activity. The principal objectives of the present study were to determine whether: (i) MCCH is conserved in independent isolates of MCV-1 and MCV-2; (ii) MCCH mRNA is expressed in vivo; and (iii) the MCCH protein is secreted from mammalian cells. The nucleotide sequence of the MCCH gene locus was determined for 27 isolates of MCV-1 and 2 of MCV-2 obtained from 29 MCV-infected individuals. In each case, the characteristic CC sequence, the NH2-terminal deletion, and the length of the open reading frame were conserved, although there were some, mostly conservative, amino acid substitutions. Since MCV cannot be propagated in cell culture, mRNA was synthesized in vitro by the early transcription apparatus in purified MCV virions. MCCH RNA was amplified by RT-PCR; the sequence included the complete open reading frame and extended 40 to 50 nucleotides past the first poxviral termination signal (TTTTTNT). Similar RT-PCR results were obtained using total cellular RNA derived from MCV-infected tissue specimens. Finally, the MCCH open reading frame was expressed in a vaccinia virus vector and the predicted size polypeptide was secreted into the medium, as determined by Western blotting. Taken together, our data support the prediction that MCV expresses a secreted chemokine homolog that could antagonize the inflammatory response in vivo.
对传染性软疣病毒（MCV-1）全基因组序列的分析揭示了一个104个氨基酸的开放阅读框（MC148R），其在结构上与趋化因子的β（CC）家族相关。预测的MCV趋化因子同源物（MCCH）在NH2末端激活域有一个缺失，提示其缺乏趋化活性。本研究的主要目的是确定：（i）MCCH在MCV-1和MCV-2的独立分离株中是否保守；（ii）MCCH mRNA在体内是否表达；以及（iii）MCCH蛋白是否从哺乳动物细胞中分泌。对从29名MCV感染个体获得的27株MCV-1和2株MCV-2的MCCH基因座的核苷酸序列进行了测定。在每种情况下，特征性的CC序列、NH2末端缺失以及开放阅读框的长度都是保守的，尽管存在一些大多为保守性的氨基酸替换。由于MCV不能在细胞培养中增殖，因此通过纯化的MCV病毒粒子中的早期转录装置在体外合成mRNA。通过RT-PCR扩增MCCH RNA；该序列包括完整的开放阅读框，并延伸至第一个痘病毒终止信号（TTTTTNT）之后40至50个核苷酸。使用源自MCV感染组织标本的总细胞RNA也获得了类似的RT-PCR结果。最后，MCCH开放阅读框在痘苗病毒载体中表达，并且通过蛋白质印迹法确定预测大小的多肽分泌到培养基中。综上所述，我们的数据支持MCV表达一种可在体内拮抗炎症反应的分泌趋化因子同源物的预测。
