Cook J R, Emanuel S L, Donnelly R J, Soh J, Mariano T M, Schwartz B, Rhee S, Pestka S
Department of Molecular Genetics and Microbiology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854-5635.
J Biol Chem. 1994 Mar 4;269(9):7013-8.
A chromosomal fragmentation procedure was employed to produce a deletion set of yeast artificial chromosomes (YACs) from a parental YAC, GART D142H8, known to map to human chromosome 21q and to encode the human interferon-gamma receptor (Hu-IFN-gamma R) accessory factor gene as well as the phosphoribosylglycinamide formyltransferase (GART) gene. When expressed in Chinese hamster ovary cells, these deleted YACs retain accessory factor activity, as judged by major histocompatibility complex class I antigen inducibility, until the deletions from the acentric end exceed 390 kilobases (kb). Therefore, the accessory factor (AF-1) gene can be localized to a 150-kb region at the left (centric) end of the parental 540-kb GART YAC. Cells containing functional YACs are also able to induce the ISGF3 gamma and gamma-activated factor (GAF) transcription factors, but were not protected against encephalomyocarditis virus (EMCV) upon treatment with Hu-IFN-gamma. Therefore, the Hu-IFN-gamma R and the AF-1 are sufficient for some, but not all, of the actions of Hu-IFN-gamma. We postulate that an additional accessory factor (AF-2) required for antiviral activity against EMCV is encoded on chromosome 21q.
采用染色体片段化程序，从亲本酵母人工染色体（YAC）GART D142H8产生一组缺失的YAC，已知该亲本YAC定位于人类21号染色体q区，编码人类干扰素-γ受体（Hu-IFN-γR）辅助因子基因以及磷酸核糖甘氨酰胺甲酰基转移酶（GART）基因。当在中华仓鼠卵巢细胞中表达时，这些缺失的YAC保留辅助因子活性，通过主要组织相容性复合体I类抗原诱导性判断，直到无着丝粒末端的缺失超过390千碱基（kb）。因此，辅助因子（AF-1）基因可定位于亲本540-kb GART YAC左端（着丝粒端）的150-kb区域。含有功能性YAC的细胞也能够诱导ISGF3γ和γ激活因子（GAF）转录因子，但在用Hu-IFN-γ处理后不能抵抗脑心肌炎病毒（EMCV）。因此，Hu-IFN-γR和AF-1对于Hu-IFN-γ的某些但不是全部作用是足够的。我们推测，针对EMCV的抗病毒活性所需的另一种辅助因子（AF-2）在21号染色体q区编码。
