Prostaglandins （PGs） play a critical role in porcine reproduction, of which prostaglandin E2 （PGE2） and prostaglandin F2a （PGF2a） exert antiluteolytic and luteolysis actions, respectively. As a rate-limiting enz...Prostaglandins （PGs） play a critical role in porcine reproduction, of which prostaglandin E2 （PGE2） and prostaglandin F2a （PGF2a） exert antiluteolytic and luteolysis actions, respectively. As a rate-limiting enzyme, carbonyl reductase 1 （CBR1） catalyzes the conversion of PGE2 to PGF2a. A high ratio of PGE2：PGF2a is beneficial to the establishment and maintenance of porcine pregnancy. PG is essential for the establishment of pregnancy which resembles the proinflammatory response and nuclear factor KB （NF-KB） is involved in the process. Bioinformatic analysis has shown that NF-KB is a possible factor bound to two cis-regulatory elements in CBRI promoter. In this study, we cloned the 2997 bp （-2875/＋122） of the promoter, and constructed six 5＇-deleted dual-luciferase reporter recombinant vectors. In endometrial cells, the region of P2 （-16401＋7） exhibited the greatest transcriptional activity at driving luciferase expression, but not significantly different from that of P1 （-2089/＋7）. The activity of P1, P2, and P3 （-1019/＋7） was highly significantly higher than that of others （P〈0.01）, suggesting that two positive regulatory elements were likely present in the regions of -1640/-1019 and -1019/-647. The results also showed that the -1640/ -647 region was indispensable for the promoter. The results of chromatin immunoprecipitation （CHIP） demonstrated that the NF-KB subunit p65 binds to one site around -15451-1531. Using four reference genes, we found that the over-expression of p65 enhanced the expression of CBR1 （P〈0.05） in porcine endometrial epithelial cells, while knockdown of the p65 did not down-regulate the CBRI expression. These results indicated that NF-KB （p65） could bind to the special element of CBR1 gene promoter in porcine endometrial epithelial cells in vitro. The binding site of NF-KB was a positive regulator for the CBR1 gene promoter, but was not necessary for the basic expression.展开更多
Rhizosphere acidification is essential for iron （Fe） uptake into plant roots. Plasma membrane （PM） H＊-ATPases play key roles in rhizosphere acidification. However, it is not fully understood how PM H＋-ATPase act...Rhizosphere acidification is essential for iron （Fe） uptake into plant roots. Plasma membrane （PM） H＊-ATPases play key roles in rhizosphere acidification. However, it is not fully understood how PM H＋-ATPase activity is regulated to enhance root Fe uptake under Fe-deficient conditions. Here, we present evidence that cytochrome b5 reductase 1 （CBR1） increases the levels of unsaturated fatty acids, which stimulate PM H＋-ATPase activity and thus lead to rhizosphere acidification. CBRl-overexpressing （CBRI-OX） Arabidopsis thaliana plants had higher levels of unsaturated fatty acids （18：2 and 18：3）, higher PM H＊-ATPase activity, and lower rhizosphere pH than wild-type plants. By contrast, cbrl loss-of-function mutant plants showed lower levels of unsaturated fatty acids and lower PM H＊-ATPase activity but higher rhizosphere pH. Reduced PM H＊-ATPase activity in cbrl could be restored in vitro by addition of unsatu- rated fatty acids. Transcript levels of CBR1, fatty acids desaturase 2 （FAD2）, and fatty acids desaturase 3 （FAD3） were increased under Fe-deficient conditions. We propose that CBR1 has a crucial role in increasing the levels of unsaturated fatty acids, which activate the PM H＊-ATPase and thus reduce rhizosphere pH. This reaction cascade ultimately promotes root Fe uptake.展开更多
基金Project supported by the National Natural Science Foundation of China(No.31201771)the Earmarked Fund for China Agriculture Research System(No.CARS-36)
文摘Prostaglandins （PGs） play a critical role in porcine reproduction, of which prostaglandin E2 （PGE2） and prostaglandin F2a （PGF2a） exert antiluteolytic and luteolysis actions, respectively. As a rate-limiting enzyme, carbonyl reductase 1 （CBR1） catalyzes the conversion of PGE2 to PGF2a. A high ratio of PGE2：PGF2a is beneficial to the establishment and maintenance of porcine pregnancy. PG is essential for the establishment of pregnancy which resembles the proinflammatory response and nuclear factor KB （NF-KB） is involved in the process. Bioinformatic analysis has shown that NF-KB is a possible factor bound to two cis-regulatory elements in CBRI promoter. In this study, we cloned the 2997 bp （-2875/＋122） of the promoter, and constructed six 5＇-deleted dual-luciferase reporter recombinant vectors. In endometrial cells, the region of P2 （-16401＋7） exhibited the greatest transcriptional activity at driving luciferase expression, but not significantly different from that of P1 （-2089/＋7）. The activity of P1, P2, and P3 （-1019/＋7） was highly significantly higher than that of others （P〈0.01）, suggesting that two positive regulatory elements were likely present in the regions of -1640/-1019 and -1019/-647. The results also showed that the -1640/ -647 region was indispensable for the promoter. The results of chromatin immunoprecipitation （CHIP） demonstrated that the NF-KB subunit p65 binds to one site around -15451-1531. Using four reference genes, we found that the over-expression of p65 enhanced the expression of CBR1 （P〈0.05） in porcine endometrial epithelial cells, while knockdown of the p65 did not down-regulate the CBRI expression. These results indicated that NF-KB （p65） could bind to the special element of CBR1 gene promoter in porcine endometrial epithelial cells in vitro. The binding site of NF-KB was a positive regulator for the CBR1 gene promoter, but was not necessary for the basic expression.
文摘Rhizosphere acidification is essential for iron （Fe） uptake into plant roots. Plasma membrane （PM） H＊-ATPases play key roles in rhizosphere acidification. However, it is not fully understood how PM H＋-ATPase activity is regulated to enhance root Fe uptake under Fe-deficient conditions. Here, we present evidence that cytochrome b5 reductase 1 （CBR1） increases the levels of unsaturated fatty acids, which stimulate PM H＋-ATPase activity and thus lead to rhizosphere acidification. CBRl-overexpressing （CBRI-OX） Arabidopsis thaliana plants had higher levels of unsaturated fatty acids （18：2 and 18：3）, higher PM H＊-ATPase activity, and lower rhizosphere pH than wild-type plants. By contrast, cbrl loss-of-function mutant plants showed lower levels of unsaturated fatty acids and lower PM H＊-ATPase activity but higher rhizosphere pH. Reduced PM H＊-ATPase activity in cbrl could be restored in vitro by addition of unsatu- rated fatty acids. Transcript levels of CBR1, fatty acids desaturase 2 （FAD2）, and fatty acids desaturase 3 （FAD3） were increased under Fe-deficient conditions. We propose that CBR1 has a crucial role in increasing the levels of unsaturated fatty acids, which activate the PM H＊-ATPase and thus reduce rhizosphere pH. This reaction cascade ultimately promotes root Fe uptake.
