Kasamatsu Jun, Suzuki Takashi, Ishijima Junko, Matsuda Yoichi, Kasahara Masanori
Department of Pathology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Immunogenetics. 2007 Apr;59(4):329-31. doi: 10.1007/s00251-007-0200-3. Epub 2007 Feb 14.
Variable lymphocyte receptors (VLR) generate enormous diversity through assembling highly diverse leucine-rich repeat (LRR) modules and presumably function as antigen receptors in jawless vertebrates. The hagfish, which constitute major extant members of jawless vertebrates along with lampreys, have two VLR genes designated VLRA and VLRB, whereas only a single VLR gene has been identified in the lamprey. In the present study, we show by fluorescence in situ hybridization (FISH) that hagfish VLRA and VLRB are located on the same chromosome, but are far apart from each other. Analysis of available inshore hagfish complementary DNA sequences indicates that VLRA and VLRB do not share a LRR module with an identical nucleotide sequence. Physical separation of VLRA and VLRB is consistent with this observation and indicates that the two VLR genes function as separate units. The FISH protocol developed in this study should be useful for the analysis of the agnathan genome.
可变淋巴细胞受体（VLR）通过组装高度多样的富含亮氨酸重复序列（LRR）模块产生巨大的多样性，并可能在无颌脊椎动物中作为抗原受体发挥作用。盲鳗与七鳃鳗一起构成了无颌脊椎动物现存的主要成员，它们有两个VLR基因，分别命名为VLRA和VLRB，而在七鳃鳗中只鉴定出了一个VLR基因。在本研究中，我们通过荧光原位杂交（FISH）表明，盲鳗的VLRA和VLRB位于同一条染色体上，但彼此相距很远。对现有的近海盲鳗互补DNA序列的分析表明，VLRA和VLRB不共享具有相同核苷酸序列的LRR模块。VLRA和VLRB的物理分离与这一观察结果一致，表明这两个VLR基因作为独立的单元发挥作用。本研究中开发的FISH方案应该有助于对无颌类基因组的分析。
