Cas9-Based Local Enrichment and Genomics Sequence Revision of Megabase-Sized Shark IgNAR Loci

作者：Dong, Hongming; Zhang, Yaolei; Wang, Jiahao; Xiang, Haitao; Lv, Tianhang; Wei, Likun; Yang, Shaosen; Liu, Xiaopan; Ren, Bingzhao; Zhang, Xiuqing; Liu, Lirong; Cao, Jun; Wang, Meiniang^*; Shi, Jiahai^*; Yang, Naibo^*

来源：Journal of Immunology, 2022, 208(1): 181-189.

DOI：10.4049/jimmunol.2100844

• ANTIGEN RECEPTOR IGNAR
• CHAIN-ONLY ANTIBODIES
• VARIABLE DOMAIN
• STRUCTURAL-ANALYSIS
• IMMUNOGLOBULIN
• REGION

The 0.8-Mb Ig new Ag receptor (IgNAR) region of the whitespotted bamboo shark (Chiloscyllium plagiosum) is incompletely assembled in Chr_44 of the reference genome. Here we used Cas9-assisted targeting of chromosome segments (CATCH) to enrich the 2 Mb region of the Chr_44 IgNAR loci and sequenced it by PacBio and next-generation sequencing. A fragment >3.13 Mb was isolated intact from the RBCs of sharks. The target was enriched 245.531-fold, and sequences had up to 94% coverage with a 2553 mean depth. Compared with the previously published sequences, 20 holes were filled, with a total length of 3508 bp. In addition, we report five potential germline V alleles of IgNAR1 from six sharks that may belong to two clusters of the IgNAR. Our results provide a new method to research the germline of large Ig gene segments, as well as provide the enhanced bamboo shark IgNAR gene loci with fewer gaps.

• 单位
  中国科学院研究生院; 深圳华大基因研究院