State Key Laboratory of Biotherapy &Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.
Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan.
Sci Rep. 2017 Jan 18;7:40416. doi: 10.1038/srep40416.
Here, we report a genome-wide survey of immunoglobulin light chain (IGL) genes of torafugu (Takifugu rubripes) revealing multi-clusters spanning three separate chromosomes (v5 assembly) and 45 scaffolds (v4 assembly). Conventional sequence similarity searches and motif scanning approaches based on recombination signal sequence (RSS) motifs were used. We found that three IGL isotypes (L1, L2, and L3) exist in torafugu and that several loci for each isotype are present. The transcriptional orientations of the variable IGL (V) segments were found to be either the same (in the L2 isotype) or opposite (in the L1 and L3 isotypes) to the IGL joining (J) and constant (C) segments, suggesting they can undergo rearrangement by deletion or inversion when expressed. Alignments of expressed sequence tags (ESTs) to corresponding germline gene segments revealed expression of the three IGL isotypes in torafugu. Taken together, our findings provide a genomic framework for torafugu IGL genes and show that the IG diversity of this species could be attributed to at least three distinct chromosomal regions.
在这里，我们报告了对torafugu（Takifugu rubripes）免疫球蛋白轻链（IGL）基因的全基因组调查，揭示了跨越三个独立染色体（v5 组装）和 45 个支架（v4 组装）的多簇。我们使用了基于重组信号序列（RSS）基序的常规序列相似性搜索和基序扫描方法。我们发现 torafugu 存在三种 IGL 同型（L1、L2 和 L3），并且每种同型都存在多个基因座。发现可变 IGL（V）片段的转录方向与 IGL 连接（J）和恒定（C）片段相同（在 L2 同型中）或相反（在 L1 和 L3 同型中），表明它们在表达时可以通过缺失或倒位进行重排。将表达序列标签（EST）与相应的胚系基因片段进行比对，揭示了 torafugu 中三种 IGL 同型的表达。总之，我们的发现为 torafugu IGL 基因提供了一个基因组框架，并表明该物种的 IG 多样性至少可以归因于三个不同的染色体区域。
