Yoder Jeffrey A, Cannon John P, Litman Ronda T, Murphy Carly, Freeman Jennifer L, Litman Gary W
Department of Molecular Biomedical Sciences and Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
Immunogenetics. 2008 May;60(5):257-65. doi: 10.1007/s00251-008-0285-3. Epub 2008 Mar 11.
Novel immune-type receptors (NITRs) are immunoglobulin-variable (V) domain-containing cell surface proteins that possess characteristic activating/inhibitory signaling motifs and are expressed in hematopoietic cells. NITRs are encoded by multigene families and have been identified in bony fish species. A single gene cluster, which encodes 36 NITRs that can be classified into 12 families, has been mapped to zebrafish chromosome 7. We report herein the presence of a second NITR gene cluster on zebrafish chromosome 14, which is comprised of three genes (nitr13, nitr14a, and nitr14b) representing two additional NITR gene families. Phylogenetic analyses indicate that the V domains encoded by the nitr13 and nitr14 genes are more similar to each other than any other zebrafish NITR suggesting that these genes arose from a tandem gene duplication event. Similar analyses comparing zebrafish Nitr13 and Nitr14 to NITRs from other fish species indicate that the nitr13 and nitr14 genes are phylogenetically related to the catfish IpNITR13 and IpNITR15 genes. Sequence features of the chromosomal region encoding nitr13 suggest that this gene arose via retrotransposition.
新型免疫型受体（NITRs）是含有免疫球蛋白可变（V）结构域的细胞表面蛋白，具有特征性的激活/抑制信号基序，并在造血细胞中表达。NITRs由多基因家族编码，已在硬骨鱼类中被鉴定出来。一个单一的基因簇已被定位到斑马鱼的7号染色体上，该基因簇编码36种NITRs，可分为12个家族。我们在此报告斑马鱼14号染色体上存在第二个NITR基因簇，它由三个基因（nitr13、nitr14a和nitr14b）组成，代表另外两个NITR基因家族。系统发育分析表明，nitr13和nitr14基因编码的V结构域彼此之间比任何其他斑马鱼NITR更相似，这表明这些基因起源于串联基因复制事件。将斑马鱼的Nitr13和Nitr14与其他鱼类的NITRs进行的类似分析表明，nitr13和nitr14基因在系统发育上与鲶鱼的IpNITR13和IpNITR15基因相关。编码nitr13的染色体区域的序列特征表明该基因是通过逆转座产生的。
