Elucidation of the evolution of the MHC by genome analysis

为了弄清染色体6p21.3(HLA区)、1q21-q25、9q33-q34和19p13.1-p13.3区四个平行区域的基因组织，以及了解HLA区的进化，我们用YAC、PAC和BAC克隆分析了CD1基因周围的HLAI类区域、9q33-q34和1q22-q23区域的基因组结构。用鸟枪法测定了1.8兆碱基(Mb)的人类白细胞抗原I类基因全长序列。在该区域共发现124个基因或候选基因序列和758个微卫星重复序列。在人类MHC的进化过程中，发现了5对序列高度同源的片段，提示在人类MHC的进化过程中可能发生了节段性基因组复制。在9q33-q34区，定位了3个在HLA区有同源基因的基因，通过对YAC克隆的PCR分析，在1q22-q23区，通过对PAC克隆末端区域的测序，构建了一个约1.8Mb的YAC和PAC重叠群，其中包含5个CD1基因。有10个基因位于CDLE的端粒一侧，其顺序为SPTA 1-MNDA-FYI-IFI-16-FCERIA-KRTC7-CRP-CRPP1-ARCS-KIAAO 120。进一步对位于KIAA 0120端粒一侧的YAC克隆进行了PCR分析，定位到12个基因：(ATP1A2-PXF-CBP-AIM2)-Lyam-(CD48-LY9-ppox)-USF1-(EAT2-Pbx1)-ALDH9-RXRG-POU2F1-CD3Z-ATAC-(Fv-ELAM1-LNHR)-FMO1-FASL。因此，CD1基因周围的1q22-q23区域包含一组具有免疫学意义的基因，如SPTA 1、FY、IFI-16、ECERIA、ARCS、LYAM、CD48、LY9、SCM、CD3Z、ATAC、ELAM1、LNHR和FASL。

In order to clarify the gene organization of four paralogous regions ; chromosome 6p21.3 (HLA region), the 1q21-q25, 9q33-q34, and 19p13.1-p13.3 regions, and understanding of the evolution of the HLA region, we have analyzed the genomic structure of the HLA class I region, 9q33-q34 and 1q22-q23 region around the CD1 genes by YAC, PAC and BAC clones. The genomic sequence of the 1.8 megabase (Mb) HLA class I entire region, was determined by the shot gun method. In total, 124 genes or candidate gene sequences and 758 microsatellite repeats were found in this region. In addition, the five pair segments which showed high sequence homology to each other were found in the HLA class I region, suggesting that segmental genome duplication must have occurred during the evolution of the human MHC, ln the 9q33-q34 region, three genes which have homologous genes in the HLA region were mapped, HXB -C5 -GRP78 from PCR analyses of the YAC clones, In the 1q22-q23 region, an approximately 1.8 Mb YAC and PAC contig containing thefive CD1 genes were constructed by PCR using locus-specific and STS primer pairs and sequencing of the end regions of PAC clones. Ten genes were located in the telomeric side of CDlE with the order of SPTA 1 - MNDA -FYI - IFI-16 -FCERIA -KRTC7 -CRP -CRPP1 -ARCS - KIAAO 120 . Further, from PCR analyses of the YAC clones which were located on the telomeric side of KIAA 0120, twelve genes were mapped, (ATP1A2 - PXF - CBP -AIM2)- LYAM - (CD48 - LY9 - PPOX) -USF1 - (EAT2 -PBX1) - ALDH9 - RXRG - POU2F1 -CD3Z - ATAC - (FV- ELAM1 - LNHR) -FMO1 - FASL between D1S1705 and WI-6210. Thus, it was revealed that the 1q22-q23 region around the CD1 genes contained a cluster of genes which had immunological importance, such as SPTA 1, FY, IFI-16, ECERIA, ARCS, LYAM, CD48, LY9, SCM, CD3Z, ATAC, ELAM1, LNHR and FASL .