State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, People's Republic of China.
Immunogenetics. 2011 Oct;63(10):667-78. doi: 10.1007/s00251-011-0545-5. Epub 2011 Jun 10.
In humans, classical MHC class II molecules include DQ, DR, and DP, which are similar in structure but consist of distinct α- and β-chains. The genes encoding these molecules are all located in the MHC class II gene region. In non-mammalian vertebrates such as chickens, only a single class II α-chain gene corresponding to the human DRA has been identified. Here, we report a characterization of the duck MHC class II α-chain (Anpl-DRA) encoding gene, which contains four exons encoding a typical signal peptide, a peptide-binding α1 domain, an immunoglobulin-like α2 domain, and Tm/Cyt, respectively. This gene is present in the duck genome as a single copy and is highly expressed in the spleen. Sequencing of cDNA and genomic DNA of the Anpl-DRA of different duck individuals/strains revealed low levels of genetic polymorphism, especially in the same strain, although most duck individuals have two different alleles. Otherwise, we found that the duck gene is located next to class II β genes, which is the same as in humans but different from the situation in chickens.
在人类中，经典 MHC Ⅱ类分子包括 DQ、DR 和 DP，它们在结构上相似，但由不同的 α-和 β-链组成。编码这些分子的基因都位于 MHC Ⅱ类基因区域。在非哺乳动物脊椎动物如鸡中，只鉴定到一个与人类 DRA 相对应的单一的Ⅱ类α链基因。在这里，我们报道了鸭 MHC Ⅱ类α链（Anpl-DRA）编码基因的特征，该基因包含四个外显子，分别编码一个典型的信号肽、肽结合的α1 结构域、免疫球蛋白样的α2 结构域和 Tm/Cyt。该基因在鸭基因组中作为单拷贝存在，在脾脏中高度表达。对不同鸭个体/品系的 Anpl-DRA 的 cDNA 和基因组 DNA 进行测序，揭示了遗传多态性水平较低，尤其是在同一品系中，尽管大多数鸭个体有两个不同的等位基因。此外，我们发现鸭基因位于 II 类β基因旁边，与人类相同，但与鸡的情况不同。
