Molecular Analysis of the HLA Gene Region by Large DNA Cloning

为了阐明人类组织相容性区域（HLA）的结构组织，我们的目标是通过粘粒和YAC克隆来克隆整个HLA区域，包括3，500 kb。今年我们建立了YAC克隆系统，获得了主要编码HLA I类基因的1450 kb的额外区域。这些区域，特别是HLA-B和-C基因周围，发现含有大量的CpG岛，表明存在新的表达基因。我们正在对这些新基因的cDNA克隆进行分离和鉴定，以探讨它们与白塞病、多发性硬化、寻常型银屑病等HLA I类相关疾病易感性的可能性。我们还在III类基因区至着丝粒侧的250 kb区域进行了基因步移，其应代表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。在该实验过程中，鉴定了编码腱生蛋白样蛋白的新基因。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，主要在淋巴细胞中表达。该基因与许多HLA-class 11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.