Prkaca consists of the catalytic subunit alpha protein kinase A (PKA), which is involved in many cellular processes. In this study, the cDNA and genomic sequences of prkaca in tilapia hybrids (Oreochromis mossambicus × Oreochromis hornorum) were cloned and analysed. The results showed the prkaca gene consists of 11 exons and 10 introns, and its protein contains 351 amino acid residues and is clustered with Oreochromis niloticus, Maylandia zebra and Haplochromis burtoni first in a phylogenetic tree. Amino acid alignment indicates that prkaca shares the highest identity (100%) to Oreochromis niloticus, Maylandia zebra and Haplochromis burtoni. Two CpG islands of prkaca were found by MethPrimer software, and 32 CG sites were found in the proximal promoter. The methylation level of prkaca in the hybrids (0.31%) was significantly lower than that of their parents (0.94% and 3.43%) in kidney tissue (P < 0.05). The gene expression levels and DNA methylation levels of prkaca in muscle and kidney tissues of the tilapia hybrids were detected by quantitative real-time PCR and bisulfite sequencing PCR and showed a negative correlation under saline-alkali stress. The results of this research demonstrated that DNA methylation levels and prkaca mRNA expression levels were inversely correlated under saline-alkali stress, implying that heterosis is likely accompanied by DNA methylation alterations. This research provides new clues for further investigations of DNA methylation and heterosis in hybrid fish.

中文翻译：

---

罗非鱼杂种（Oreochromis mossambicus×Oreochromis hornorum）渗透压调节过程所涉及的prkaca基因的DNA甲基化。

Prkaca由催化亚基α蛋白激酶A（PKA）组成，它参与许多细胞过程。本研究克隆并分析了罗非鱼杂种（莫桑比克莫桑比克×霍罗非鱼）中的普卡卡的cDNA和基因组序列。结果表明，prkaca基因由11个外显子和10个内含子组成，其蛋白质包含351个氨基酸残基，并在系统发育树中首先与尼罗罗非鱼，马兰德斑马和博登嗜血杆菌聚类。氨基酸比对表明，普尔卡卡人与尼罗罗非鱼，斑马鱼和斑马线虫具有最高的同一性（100％）。通过MethPrimer软件发现了prkaca的两个CpG岛，并且在近端启动子中发现了32个CG位点。杂种中prkaca的甲基化水平（0。31％）的肾脏组织显着低于其父母（0.94％和3.43％）（P <0.05）。通过定量实时荧光定量PCR和亚硫酸氢盐测序PCR检测罗非鱼杂种肌肉和肾脏组织中prkaca的基因表达水平和DNA甲基化水平，在盐碱胁迫下呈负相关。这项研究的结果表明，在盐碱胁迫下，DNA甲基化水平和prkaca mRNA表达水平呈负相关，这表明杂种优势很可能伴随着DNA甲基化改变。该研究为杂交鱼DNA甲基化和杂种优势的进一步研究提供了新的线索。通过实时定量PCR和亚硫酸氢盐测序PCR检测罗非鱼杂种肌肉和肾脏组织中prkaca的基因表达水平和DNA甲基化水平，在盐碱胁迫下呈负相关。这项研究的结果表明，在盐碱胁迫下，DNA甲基化水平和prkaca mRNA表达水平呈负相关，这表明杂种优势很可能伴随着DNA甲基化改变。该研究为杂交鱼DNA甲基化和杂种优势的进一步研究提供了新的线索。通过定量实时荧光定量PCR和亚硫酸氢盐测序PCR检测罗非鱼杂种肌肉和肾脏组织中prkaca的基因表达水平和DNA甲基化水平，在盐碱胁迫下呈负相关。这项研究的结果表明，在盐碱胁迫下，DNA甲基化水平和prkaca mRNA表达水平呈负相关，这表明杂种优势很可能伴随着DNA甲基化改变。该研究为杂交鱼DNA甲基化和杂种优势的进一步研究提供了新的线索。这项研究的结果表明，在盐碱胁迫下，DNA甲基化水平和prkaca mRNA表达水平呈负相关，这表明杂种优势很可能伴随着DNA甲基化改变。该研究为杂交鱼DNA甲基化和杂种优势的进一步研究提供了新的线索。这项研究的结果表明，在盐碱胁迫下，DNA甲基化水平和prkaca mRNA表达水平呈负相关，这表明杂种优势很可能伴随着DNA甲基化改变。该研究为杂交鱼DNA甲基化和杂种优势的进一步研究提供了新的线索。