Molecular Analysis of the HLA Gene Region by Large DNA Cloning

为了阐明人类组织相容区的结构组织，我们通过粘粒克隆和YAC克隆的方法克隆了全长3,500kb的人类组织相容区。在这一年中，我们已经建立了YAC克隆系统，并可以获得额外的1450kb的区域，主要编码HLAI类区域。这些区域，特别是在人类白细胞抗原-B和-C基因附近，被发现含有大量的CpG岛，这表明存在新的表达基因。从这些新基因中分离和鉴定CDNA克隆的工作正在进行中，以寻求它们可能与一些人类白细胞抗原I类相关疾病的易感性有关，如白塞病、多发性硬化症、寻常型银屑病等。我们还在250kb的区域进行了基因行走，从III类区域到着丝粒一侧，这应该代表了GC富集区和AT富集区之间的遗传边界。对该区域粘粒DNA的分析表明，富含GC到富含AT的变化是不连续的，但不是连续的。在这个实验过程中，一个新的编码Tenascin样蛋白的基因被鉴定出来。该基因含有纤维连接蛋白III和EGF重复序列，具有纤维蛋白原样结构域，主要在淋巴样细胞中表达。这一新基因与许多人类白细胞抗原11类相关疾病的相关性将被研究，以了解该基因的功能。

In order to clarify structural organization of the human histocompatibility region, (HLA) we aimed to clone the whole HLA region encompassing 3, 500kb by cosmid and YAC cloning. In this year, we have established the YAC cloning system and could obtained the additional 1, 450kb region mainly encoding the HLA class I region. These region, especially around the HLA-B and -C genes, was found to contains numerous CpG islands which indicate the presence of new expressed gene. Isolation and characterization of CDNA clones from these new genes are under way to pursuit the possibility that they are responsible for the susceptibility to some HLA class I -associated diseases such as Behcet disease, multiple sclerosis, psoriasis vulgaris et al.We have also gene-walked in the 250kb region to the centromeric side from the class III region, which should represent the genetic boundary between the GC rich and AT rich - region. Analysis of the cosmid DNAs from this region indicated that the GC rich to AT rich change occurred discontinuously, but not successively. During the course of this experiment a new gene encoding the tenascin-like protein was identified. This gene contained the fibronection III and EGF repeats with the fibrinogen-like domain and was mainly expressed in the lymphoid cells. Correlation of this new gene with a lot of the HLA- class 11 associated diseases will be investigated to understand the function of this gene.