Lötzerich Mark, Ruzsics Zsolt, Koszinowski Ulrich H
Max von Pettenkofer Institut, Pettenkoferstrasse 9a, 80336 Munich, Germany.
J Virol. 2006 Jan;80(1):73-84. doi: 10.1128/JVI.80.1.73-84.2006.
Two conserved herpes simplex virus 1 proteins, UL31 and UL34, form a complex at the inner nuclear membrane which governs primary envelopment and nuclear egress of the herpesvirus nucleocapsids. In mouse cytomegalovirus, a member of the betaherpesvirus subfamily, the homologous proteins M53/p38 and M50/p35 form the nuclear egress complex (NEC). Since the interaction of these proteins is essential for functionality, the definition of the mutual binding sites is a prerequisite for further analysis. Using a comprehensive random mutagenesis procedure, we have mapped the M53/p38 binding site of M50/p35 (A. Bubeck, M. Wagner, Z. Ruzsics, M. Lötzerich, M. Iglesias, I. R. Singh, and U. H. Koszinowski, J. Virol. 78:8026-8035). Here we describe a corresponding analysis for the UL31 homolog M53/p38. A total of 72 individual mutants were reinserted into the genome to test the complementation of the lethal M53 null phenotype. The mutants were also studied for colocalization and for coprecipitation with M50/p35. The analysis revealed that the nonconserved N-terminal one-third of M53/p38 provides the nuclear localization signal as an essential function. The collective results for many mutants localized the binding site for M50/p35 to amino acids (aa) 112 to 137. No single aa exchange for alanine could destroy NEC formation, but virus attenuation revealed a major role for aa K128, Y129, and L130. The lethal phenotype of several insertion and stop mutants indicated the functional importance of the C terminus of the protein.
两种保守的单纯疱疹病毒1型蛋白,UL31和UL34,在内核膜处形成复合物,该复合物控制疱疹病毒核衣壳的初级包膜化和核出芽。在β疱疹病毒亚科成员小鼠巨细胞病毒中,同源蛋白M53/p38和M50/p35形成核出芽复合物(NEC)。由于这些蛋白的相互作用对于其功能至关重要,因此确定相互结合位点是进一步分析的前提条件。我们使用全面的随机诱变程序,绘制了M50/p35的M53/p38结合位点(A. Bubeck、M. Wagner、Z. Ruzsics、M. Lötzerich、M. Iglesias、I. R. Singh和U. H. Koszinowski,《病毒学杂志》78:8026 - 8035)。在此,我们描述了对UL31同源物M53/p38的相应分析。总共72个单独的突变体被重新插入基因组中,以测试致死性M53缺失表型的互补情况。还研究了这些突变体与M50/p35的共定位和共沉淀情况。分析表明,M53/p38非保守的N端三分之一提供核定位信号作为一项基本功能。许多突变体的综合结果将M50/p35的结合位点定位到氨基酸(aa)112至137。没有单个丙氨酸替代氨基酸的交换能够破坏NEC的形成,但病毒减毒显示aa K128、Y129和L130起主要作用。几个插入和终止突变体的致死表型表明该蛋白C端的功能重要性。