Fleming S B, Blok J, Fraser K M, Mercer A A, Robinson A J
Health Research Council Virus Research Unit, Dunedin, New Zealand.
Virology. 1993 Jul;195(1):175-84. doi: 10.1006/viro.1993.1358.
A 3.3-kb BamHI fragment from the center of the orf virus (OV) NZ2 genome has been sequenced, revealing three major open reading frames (ORFs) with homology to vaccinia virus (VAC) genes. These ORFs have been designated F2L, F3R, and F4R and the proteins they encode were found to be homologous to VAC genes H4L (RNA polymerase-associated protein RAP94), H5R (35-kDa virion envelope antigen) and H6R (topoisomerase), respectively. The OV ORFs are arranged on the genome in an almost identical manner to their VAC counterparts revealing the common evolutionary origin of the two viruses despite the extreme difference in their G+C content. Like its VAC counterpart, F3R was shown to be transcribed early and late during infection. S1 and primer extension analysis located the 5' ends of F3R early transcripts to a position 15-16 nt and 5-10 nt, respectively, downstream from an AT-rich sequence resembling a VAC early promoter. The 5' ends of F3R late transcripts were located to an A within the sequence 5'-TAAAG, 41 nt downstream from the early promoter and 17 nt upstream from the initiation codon. S1 analysis of F2L, which is transcribed only late in infection, revealed transcripts initiating from within the sequence 5'-TAAATG. No transcriptional start point could be detected for F4R but the VAC late transcriptional initiation sequence TAAAT was found close to the predicted translational start point. Another late promoter-like sequence, 5'-TAAATG, was found at the 3' end of F2L. This preceded a short ORF tentatively designated as F1L and predicted to be the beginning of a homologue of VAC H3L.
已对来自orf病毒（OV）NZ2基因组中心的一段3.3kb BamHI片段进行了测序，结果显示有三个主要的开放阅读框（ORF）与痘苗病毒（VAC）基因具有同源性。这些ORF被命名为F2L、F3R和F4R，发现它们编码的蛋白质分别与VAC基因H4L（RNA聚合酶相关蛋白RAP94）、H5R（35kDa病毒粒子包膜抗原）和H6R（拓扑异构酶）同源。OV的ORF在基因组上的排列方式与其VAC对应物几乎相同，这揭示了两种病毒共同的进化起源，尽管它们的G+C含量差异极大。与它的VAC对应物一样，F3R在感染的早期和晚期均有转录。S1和引物延伸分析表明，F3R早期转录本的5'端分别位于一个富含AT的序列下游15 - 16个核苷酸和5 - 10个核苷酸处，该富含AT的序列类似于VAC早期启动子。F3R晚期转录本的5'端位于序列5'-TAAAG中的一个A处，在早期启动子下游41个核苷酸处，起始密码子上游17个核苷酸处。对仅在感染后期转录的F2L进行S1分析，结果显示转录本从序列5'-TAAATG内起始。未检测到F4R的转录起始点，但发现VAC晚期转录起始序列TAAAT靠近预测的翻译起始点。在F2L的3'端发现了另一个类似晚期启动子的序列，即5'-TAAATG。它位于一个暂定为F1L的短ORF之前，预计是VAC H3L同源物的起始部分。
