Cloning Of ENaCα Subunit CDNA And Its Expression In Renal Cortex Cells Treated With Two Hormones From Alashan Bactrian Camel

Epithelial Sodium Channel(ENa C)is the main regulator for the absorption and reabsorption of salt and water in various epidermal tissues.ENa C mainly distributes in the distal tubules of renal tubules,and its basic physiological function is to transport sodium ions through membrane.Aldosterone and angiotensin II play an important role in the transmembrane transport of sodium by ENa C.It is not clear how the ENa C works in the water and salt metabolism,which is a unique physiological function of the bactrian camel,which helps bactrian camel much more tolerant to salt and drought than other domestic animals.Alax bactrian camel,lived in Inner Mongolia,was selected as research object in our work.We cloned the ENa Cα c DNA of the bactrian camel,and moreover,the total length of the cloned c DNA sequence was 1956 bp.According to homology analysis,we discovered that ENa Cα exhibited separately 81.68%,76.67% and 93.28% homology at nucleotide level,while it shared 79.11%,75.50% and 93.17% homology at amino acid level respectively,compared bactrian camel with human,mouse and dromedary camel.Nonhomologous sequence may not influence the formation of functional domain on protein structure.The mean levels of nucleotide and amino acid were severally 87.76%and 85.76% based on the above data.We further constructed the phylogenetic tree of ENa Cα with ten species which included bactrian camel,dromedary camel,human,mouse,wild boar,chimp,cattle,sheep,small brown bat and domestic cat.Then,in the light of ENa Cα,the phylogenetic trees obviously pointed out the evolutionary position of bactrian camel adjacent to dromedary camel,but far to mouse.The renal cortex cells of bactrian camel were cultured with different concentrations of aldosterone or angiotensin II,selected as experiment groups.Weset renal cortex cells cultured without aldosterone or angiotensin II as control group.By quantitative PCR,we detected the expression levels of ENa Cα in the renal cortex cells both of experiment groups and control group.The results showed that the expression levels of ENa Cα emerged separately 65%(aldosterone treated)and 50%(angiotensin II treated)increase under 1×10-9mol/L concentration compared experiment groups with control group,which changes of expression level were significantly different(P<0.01).However,under 1×10-6mol/L,1×10-7mol/L and 1×10-8mol/L aldosterone or angiotensin II,the expression levels of ENa Cα decreased by 58%,47% and 57% with aldosterone,but 34%,59% and 44% with angiotensin II,changes as significant difference(P<0.01).In the 1×10-6mol/L concentration,the expression level of ENa Cα was significantly lower with aldosterone than with angiotensin II(P<0.05),while the differences of ENa Cα expressed level were not significant(P>0.05)between aldosterone and angiotensin II under 1×10-7mol/L or 1×10-8mol/L concentration.To summarize,our ENa Cα-related research provided the theories foundation for regulation mechanism of salt-and drought-resistence on the bactrian camel.