State Key Laboratory of AgroBiotechnology, College of Biological Sciences, China Agricultural University, Beijing, People's Republic of China.
PLoS One. 2011 Feb 25;6(2):e16889. doi: 10.1371/journal.pone.0016889.
The genomic organization of the IgH (Immunoglobulin heavy chain), Igκ (Immunoglobulin kappa chain), and Igλ (Immunoglobulin lambda chain) loci in the African elephant (Loxodonta africana) was annotated using available genome data. The elephant IgH locus on scaffold 57 spans over 2,974 kb, and consists of at least 112 V(H) gene segments, 87 D(H) gene segments (the largest number in mammals examined so far), six J(H) gene segments, a single μ, a δ remnant, and eight γ genes (α and ε genes are missing, most likely due to sequence gaps). The Igκ locus, found on three scaffolds (202, 50 and 86), contains a total of 153 V(κ) gene segments, three J(κ) segments, and a single C(κ) gene. Two different transcriptional orientations were determined for these V(κ) gene segments. In contrast, the Igλ locus on scaffold 68 includes 15 V(λ) gene segments, all with the same transcriptional polarity as the downstream J(λ)-C(λ) cluster. These data suggest that the elephant immunoglobulin gene repertoire is highly diverse and complex. Our results provide insights into the immunoglobulin genes in a placental mammal that is evolutionarily distant from humans, mice, and domestic animals.
使用可用的基因组数据注释了非洲象（Loxodonta africana）的 IgH（免疫球蛋白重链）、Igκ（免疫球蛋白 κ 链）和 Igλ（免疫球蛋白 λ 链）基因座的基因组组织。第 57 号支架上的大象 IgH 基因座跨越超过 2974 kb，包含至少 112 个 V(H)基因片段、87 个 D(H)基因片段（迄今为止在哺乳动物中检测到的最多）、6 个 J(H)基因片段、一个 μ 、一个 δ 残余物和八个 γ 基因（α 和 ε 基因缺失，很可能是由于序列间隙）。在三个支架（202、50 和 86）上发现的 Igκ 基因座包含总共 153 个 V(κ)基因片段、三个 J(κ)片段和一个 C(κ)基因。这些 V(κ)基因片段确定了两个不同的转录方向。相比之下，68 号支架上的 Igλ 基因座包含 15 个 V(λ)基因片段，所有这些基因片段都与下游 J(λ)-C(λ)簇具有相同的转录极性。这些数据表明，大象免疫球蛋白基因库高度多样化和复杂。我们的研究结果为进化上远离人类、老鼠和家畜的胎盘哺乳动物的免疫球蛋白基因提供了深入了解。
