Guo Hong-Hong, Sun Yuan, Zhang Xue-Li, Jiang Xia-Yun, Zou Shu-Ming
Genetics and Breeding Center for Blunt Snout Bream, Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China.
Fish Physiol Biochem. 2019 Jun;45(3):1141-1152. doi: 10.1007/s10695-019-00625-6. Epub 2019 Apr 8.
The CITED3 protein is a non-DNA-binding transcriptional co-regulator involved in the regulation of various transcriptional responses against hypoxia stress. Here, we characterized two paralogs Cited3 genes (Cited3a and Cited3b) from blunt snout bream (Megalobrama amblycephala), which is a hypoxia-sensitive species. Both genes have an open reading frame of 756 and 723 bp; encoded a protein of 251 amino acid and 240 amino acid, respectively; and they shared a sequence identity of 67%. In adult fish, both Cited3a and Cited3b mRNAs were highly expressed in kidney tissues. In contrast, they were detected in the skin, muscle, and gonad at extraordinarily low levels. During embryogenesis, both Cited3a and Cited3b mRNAs were maternally deposited in eggs and fluctuated from the zygote to the 44-hpf (hours post-fertilization) larvae. Whole-mount in situ hybridization demonstrated that both Cited3a and Cited3b mRNAs were transcribed in the brain, gut, and tailbud at 12 hpf, and at the brain and gut at 24 hpf, and at the brain at 36 hpf embryos. Hypoxic treatment led to upregulated expression of the Cited3 genes during embryogenesis. Under hypoxia, both Cited3a and Cited3b genes in the kidney and brain and Cited3a genes in the liver were significantly upregulated. These results suggest that hypoxia was associated with increases in mRNA levels for both Cited3a (kidney, brain, liver) and Cited3b (kidney and liver).
CITED3蛋白是一种非DNA结合转录共调节因子，参与调节针对缺氧应激的各种转录反应。在此，我们鉴定了来自团头鲂（一种对缺氧敏感的物种）的两个同源Cited3基因（Cited3a和Cited3b）。这两个基因的开放阅读框分别为756和723 bp；分别编码251个氨基酸和240个氨基酸的蛋白质；它们的序列同一性为67%。在成年鱼中，Cited3a和Cited3b mRNA在肾脏组织中均高度表达。相比之下，在皮肤、肌肉和性腺中检测到的水平极低。在胚胎发育过程中，Cited3a和Cited3b mRNA均由母体沉积在卵中，并从受精卵到受精后44小时（hpf）的幼虫阶段发生波动。整体原位杂交表明，Cited3a和Cited3b mRNA在受精后12小时（hpf）时在脑、肠和尾芽中转录，在24 hpf时在脑和肠中转录，在36 hpf胚胎时在脑中转录。缺氧处理导致胚胎发育过程中Cited3基因的表达上调。在缺氧条件下，肾脏和脑中的Cited3a和Cited3b基因以及肝脏中的Cited3a基因均显著上调。这些结果表明，缺氧与Cited3a（肾脏、脑、肝脏）和Cited3b（肾脏和肝脏）的mRNA水平升高有关。
