Characterization of two kcnk3 genes in Nile tilapia (Oreochromis niloticus): Molecular cloning, tissue distribution, and transcriptional changes in various salinity of seawater

• Published in: Genomics (San Diego, Calif.) Calif.), 2020-05, Vol.112 (3), p.2213-2222
• Main Authors: Wen, Zheng-Yong, Bian, Chao, You, Xinxin, Zhang, Xinhui, Li, Jia, Zhan, Qiuyao, Peng, Yuxiang, Li, Yuan-You, Shi, Qiong
• Format: Article
• Language: English
• Subjects: Animals; Cloning, Molecular; Fish Proteins - chemistry; Fish Proteins - classification; Fish Proteins - genetics; Fish Proteins - metabolism; Gene structure; Genome; Genomic survey; kcnk3 cluster; kcnk3 gene; Models, Molecular; Nerve Tissue Proteins - chemistry; Nerve Tissue Proteins - classification; Nerve Tissue Proteins - genetics; Nerve Tissue Proteins - metabolism; Nile Tilapia (Oreochromis niloticus); Osmoregulation; Phylogenetic analysis; Phylogeny; Potassium Channels, Tandem Pore Domain - chemistry; Potassium Channels, Tandem Pore Domain - classification; Potassium Channels, Tandem Pore Domain - genetics; Potassium Channels, Tandem Pore Domain - metabolism; Protein Conformation; Salinity; Seawater; Sequence Alignment; Sequence Analysis, Protein; Tilapia - genetics; Tilapia - metabolism; Tissue Distribution; Transcription Factors - genetics; Transcription, Genetic
• ISSN: 0888-7543; 1089-8646
• DOI: 10.1016/j.ygeno.2019.12.017

As one important member of the two-pore-domain potassium channel (K2P) family, potassium channel subfamily K member 3 (KCNK3) has been reported for thermogenesis regulation, energy homeostasis, membrane potential conduction, and pulmonary hypertension in mammals. However, its roles in fishes are far less examined and published. In the present study, we identified two kcnk3 genes (kcnk3a and kcnk3b) in an euryhaline fish, Nile tilapia (Oreochromis niloticus), by molecular cloning, genomic survey and laboratory experiments to investigate their potential roles for osmoregulation. We obtained full-length coding sequences of the kcnk3a and kcnk3b genes (1209 and 1173 bp), which encode 402 and 390 amino acids, respectively. Subsequent multiple sequence alignments, putative 3D-structure model prediction, genomic survey and phylogenetic analysis confirmed that two kcnk3 paralogs are widely presented in fish genomes. Interestingly, a DNA fragment inversion of a kcnk3a cluster was found in Cypriniforme in comparison with other fishes. Quantitative real-time PCRs demonstrated that both the tilapia kcnk3 genes were detected in all the examined tissues with a similar distribution pattern, and the highest transcriptions were observed in the heart. Meanwhile, both kcnk3 genes in the gill were proved to have a similar transcriptional change pattern in response to various salinity of seawater, implying that they might be involved in osmoregulation. Furthermore, three predicted transcription factors (arid3a, arid3b, and arid5a) of both kcnk3 genes also showed a similar pattern as their target genes in response to the various salinity, suggesting their potential positive regulatory roles. In summary, we for the first time characterized the two kcnk3 genes in Nile tilapia, and demonstrated their potential involvement in osmoregulation for this economically important fish. •Two kcnk3 genes (kcnk3a and kcnk3b) were identified from Nile tilapia by molecular cloning.•Both kcnk3 genes are highly conserved among vertebrates including fishes.•A special kcnk3a cluster reversal was found in Cypriniformes fishes by a genomic survey.•Tilapia kcnk3a and kcnk3b genes showed a similar tissue distribution pattern, with the highest transcription in heart.•Both two kcnk3 genes are involved in osmoregulation roles in Nile tilapia.