Recombination activating genes () mediates the process of rearrangement and somatic recombination (V(D)J) to generate different antibody repertoire. Studies on the expression pattern of adaptive immune genes during ontogenic development are crucial for the formulation of fish immunization strategy. In the present study, Nile tilapia was taken to explore the relative expression profile of genes during their developmental stages. The developmental stages of Nile tilapia, i.e., unfertilized egg, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28 and 30 days post-hatch (dph) and kidney, blood, gill, liver and spleen tissues from adult fish were collected and the cDNA synthesis was carried out. Gene specific primers for and of Nile tilapia were designed and their annealing temperature (Tm) was optimized by gradient PCR. Consequently, PCR was performed to confirm the specific amplification of and genes. Quantitative real-time PCR (qRT-PCR) gene expression of and were noticed in all the developmental stages; however, a significant increase was observed after 12 dph and peaked at 24 dph, followed by a gradual decrease until 30 dph. Tissue-specific gene expression profiling revealed that the highest expression of and was observed in the kidney, followed by spleen, gill, liver and blood. The findings of the study explored the suitable timing of lymphoid maturation that could be technically used for the adoption of strategies to improve disease resistance of fish larvae for mitigating larval mortality.

中文翻译：

---

尼罗罗非鱼 Oreochromisniloticus 发育过程中重组激活基因 (RAG) 的个体发育和组织特异性表达谱

重组激活基因 () 介导重排和体细胞重组 (V(D)J) 的过程，以产生不同的抗体库。研究个体发育过程中适应性免疫基因的表达模式对于鱼类免疫策略的制定至关重要。在本研究中，以尼罗罗非鱼为对象，探索其发育阶段基因的相对表达谱。尼罗罗非鱼的发育阶段，即未受精卵，孵化后0、2、4、6、8、10、12、14、16、18、20、22、24、26、28和30天（dph）收集成鱼的肾脏、血液、鳃、肝脏和脾脏组织并进行cDNA合成。设计了尼罗罗非鱼的基因特异性引物，并通过梯度 PCR 优化了它们的退火温度 (Tm)。因此，进行PCR以确认和基因的特异性扩增。在所有发育阶段均观察到 和 的实时定量 PCR (qRT-PCR) 基因表达；然而，在 12 dph 后观察到显着增加，并在 24 dph 时达到峰值，随后逐渐下降，直到 30 dph。组织特异性基因表达谱显示，在肾脏中观察到 和 的表达量最高，其次是脾脏、鳃、肝脏和血液。该研究的结果探索了淋巴成熟的合适时机，从技术上讲，该时机可用于采取提高鱼类幼虫抗病性的策略，从而降低幼虫死亡率。