MDV VP22的N1-18是发挥蛋白转导功能必需的序列

血清Ⅰ型马立克氏病病毒(MDV-1)CVI988/Rispens弱毒株的VP22蛋白缺失201TKSERT206.为了进一步证实该缺失对MDV-1 VP22蛋白转导功能和效率的影响,本研究通过将不同缺失型的VP22与EGFP相融合,转染COS-1细胞,通过间接免疫荧光方法,检测VP22的蛋白转导现象.结果发现,EGFP-VP22具有微管结合、核膜结合、核酸结合、蛋白转导等特性;CVI988 VP22与GA株VP22的转导效率相当,且只有完整长度的VP22具有明显的转导功能,其中,N端1～18 aa对VP22的核定位及其蛋白转导功能的发挥意义很大.这一发现为利用MDV-1 VP22携带其他目的蛋白转导,增强目的蛋白免疫原性及其治疗性功能具有重要的指导价值.

The N1～18 Terminus of Marek's Disease Virus VP22 Is Essential for Protein Transduction

We previously showed some differences in Marek's disease virus (MDV) VP22 gene between virulent and avirulent strains, in the deletion from 201aa to 206aa, namely 201TKSERT206. In this study, VP22 genes were amplified from strains: CVI988/Rispens and GA. And then the fragments were subcloned into pcDNA3.1/zeo(+), respectively, which were co-expressed with an enhancer green fluorescent protein (EGFP) after transfection into COS-1 cells. As with both human herpesvirus 1 and bovine herpesvirus 1 VP22-EGFP fusion proteins, the subcellular localization of the three MDV EGFP-VP22 products revealed few differences, which bind to microtubules and nucleus membrane, and then to heterochromatin. In addition, VP22s also bind to centrosomes and inter-membrane. During mitosis, EGFP-VP22s bind to sister chromatids, but dissociates from the centrosomes and the microtubules of the mitotic spindle. In truncated fragments' transfection experiments, stained with the specific monoclonal antibody against VP22, it concluded that the full length of VP22 was required for protein transduction, and N1-18aa was essential to VP22 translocating from cytoplasm to nucleus as a potential nucleus localization site in the absence of other viral factors in MDV-1.