Vanderheijden N, Alard P, Lecomte C, Martial J A
Laboratoire de Biologie Moléculaire et de Génie Génétique, Université de Liège, Sart-Tilman, Belgium.
Virology. 1996 Apr 15;218(2):422-6. doi: 10.1006/viro.1996.0214.
A wild-type strain of channel catfish virus was compared at the genomic level with the attenuated strain V60. In addition to several minor differences, restriction mapping revealed one major deletion (approximately 1200 bp) in ORF50 of the V60 strain. Cloning and sequencing of part of this ORF confirmed the presence of a 1164-bp deletion. It should result in a protein of 282 amino acids instead of 670. The predicted truncated protein lacks most of a threonine-rich, highly repetitive region in its central part. Since the protein encoded by ORF50 possesses a hydrophobic N-terminal leader sequence and no membrane anchor sequence, we suggest that it could be a secreted glycoprotein. This protein might be N-glycosylated (35 potential sites) and, given the repetitive arrangement of its residues (mainly threonines), also heavily O-glycosylated like the mucin-type glycoproteins. The deletion observed in ORF50 of the V60 strain implies the loss of 24 potential N-glycosylation sites and should considerably reduce the extent of O-glycosylation.
将野生型斑点叉尾鮰病毒株与减毒株V60进行了基因组水平的比较。除了一些微小差异外，限制性酶切图谱显示V60株的ORF50中存在一个主要缺失（约1200 bp）。对该ORF部分片段的克隆和测序证实存在1164 bp的缺失。这应该会产生一个282个氨基酸的蛋白质，而不是670个氨基酸的蛋白质。预测的截短蛋白在其中心部分缺少大部分富含苏氨酸的高度重复区域。由于ORF50编码的蛋白具有疏水的N端前导序列且无膜锚定序列，我们认为它可能是一种分泌型糖蛋白。该蛋白可能进行N-糖基化（35个潜在位点），并且鉴于其残基（主要是苏氨酸）的重复排列，也可能像粘蛋白型糖蛋白一样进行大量O-糖基化。在V60株的ORF50中观察到的缺失意味着24个潜在N-糖基化位点的丢失，并且应该会大大降低O-糖基化的程度。
