Huang S, Hanson L A
College of Veterinary Medicine, Mississippi State University, Mississippi 39762, USA.
J Virol. 1998 Mar;72(3):1910-7. doi: 10.1128/JVI.72.3.1910-1917.1998.
To identify promoter regions that impart differential temporal regulation of channel catfish virus (CCV) genes, the transcriptional kinetics of an immediate-early gene and prospective early and late genes were characterized. A cDNA clone, designated IE3C, representing a third immediate-early transcript was identified. The 5' end of the IE3C transcript was mapped to nucleotides 15,368 and 131,043 in the terminal repeat regions of the CCV genome. The full length of the transcript represented by the IE3C clone is 1,412 bp, and it most likely codes for the protein specified by open reading frame (ORF) 12. The putative product of ORF12 contains a consensus RING finger metal binding motif (C3HC4 structure). Temporal expression studies, in conjunction with protein synthesis and DNA replication inhibition, demonstrated that the IE3C transcript belongs to an immediate-early kinetic class, the ORF5 transcript is a member of the early kinetic class, and ORF39 and ORF46 are true late-kinetic-class genes. Additionally, we demonstrated that ORF38 transcription overlaps ORF39 and the products presumably share the same poly(A) signal. The 5' ends of the transcripts encoding ORF38, ORF39, and ORF46 were mapped to nucleotides 44,862, 45,254, and 59,644, respectively, and potential transcriptional control elements were located.
为了鉴定赋予斑点叉尾鮰病毒（CCV）基因不同时间调控的启动子区域，对一个立即早期基因以及预期的早期和晚期基因的转录动力学进行了表征。鉴定出一个cDNA克隆，命名为IE3C，它代表第三个立即早期转录本。IE3C转录本的5'端定位于CCV基因组末端重复区域的第15368和131043个核苷酸处。由IE3C克隆代表的转录本全长为1412 bp，它很可能编码由开放阅读框（ORF）12指定的蛋白质。ORF12的推定产物包含一个共有RING指金属结合基序（C3HC4结构）。时间表达研究结合蛋白质合成和DNA复制抑制表明，IE3C转录本属于立即早期动力学类别，ORF5转录本是早期动力学类别的成员，而ORF39和ORF46是真正的晚期动力学类别基因。此外，我们证明ORF38转录与ORF39重叠，其产物可能共享相同的聚腺苷酸化信号。编码ORF38、ORF39和ORF46的转录本的5'端分别定位于第44862、45254和59644个核苷酸处，并定位了潜在的转录控制元件。
