Schiffenbauer J, Didier D K, Klearman M, Rice K, Shuman S, Tieber V L, Kittlesen D J, Schwartz B D
J Immunol. 1987 Jul 1;139(1):228-33.
The HLA-D region is composed of three subregions termed DR, DQ, and DP. We previously reported the sequence of a DR5 beta I and two DR5 beta III cDNA from the DR5 cell line Swei. We now report on the nucleotide and deduced amino acid sequence of the DQ alpha and DQ beta cDNA from the same DR5 cell line, which also types as DQw3. Comparison with other available DQ sequences indicates that DQ alpha has one region of major variability, whereas DQ beta appears to have four regions of variability. In addition, these comparisons indicate that DQw3 alpha from DR5 is different from DQw3 alpha from DR4, but identical to DQw2 alpha from DR3. In contrast, DQw3 beta from DR5 is very similar to DQw3 beta from DR4. These data indicate that at least for DQw2 and DQw3 it is the DQ beta chain that is responsible for DQ typing. Most sequence differences in DQ alleles can be attributed to point mutations; however, codon additions/deletions in the DQ alpha chain may contribute to variability. In addition, regions of possible gene conversion in the DQ alpha and DQ beta chains is suggested by the presence of a chi-like sequence in each chain. Finally, comparison of available haplotypes suggest recombination events may take place between DQ beta and DQ alpha, between DQ alpha and DR beta I, and between DR beta I and DR beta III.
HLA - D区域由三个子区域组成，分别称为DR、DQ和DP。我们之前报道了来自DR5细胞系Swei的一条DR5βI和两条DR5βIII cDNA的序列。我们现在报道来自同一DR5细胞系的DQα和DQβcDNA的核苷酸序列及推导的氨基酸序列，该细胞系也分型为DQw3。与其他可用的DQ序列比较表明，DQα有一个主要可变区，而DQβ似乎有四个可变区。此外，这些比较表明，来自DR5的DQw3α与来自DR4的DQw3α不同，但与来自DR3的DQw2α相同。相反，来自DR5的DQw3β与来自DR4的DQw3β非常相似。这些数据表明，至少对于DQw2和DQw3来说，负责DQ分型的是DQβ链。DQ等位基因中的大多数序列差异可归因于点突变；然而，DQα链中的密码子添加/缺失可能导致变异性。此外，DQα和DQβ链中存在类chi序列，提示可能存在基因转换区域。最后，对可用单倍型的比较表明重组事件可能发生在DQβ和DQα之间、DQα和DRβI之间以及DRβI和DRβIII之间。
