It has been hypothesized that under iron stress high ferric chelate reductase (FCR) activity in the absorptive root of plants tolerant to iron_deficiency will be induced and result in subsequent Fe 2+ transport a...It has been hypothesized that under iron stress high ferric chelate reductase (FCR) activity in the absorptive root of plants tolerant to iron_deficiency will be induced and result in subsequent Fe 2+ transport across the plasmalemma. The activity of FCR and expression of FCR gene (FRO2) in Citrus junos Sieb. ex Tanaka tolerant to iron_deficiency and Poncirus trifoliata (L.) Raf. susceptible to iron_deficiency were determined to elucidate the physiological difference which causes the different tolerance of the two citrus rootstocks to iron stress. The activity of FCR was detectable in excised roots and was stimulated about 20_times in C. junos and only about 3_times in P. trifoliata under iron deficiency for four weeks. The FRO2 of Arabidopsis was used as a probe, the tissue print technique was used to ascertain the expression of the FCR gene in C. junos and P. trifoliata under iron stress. High_level transcripts were observed in the absorptive root, young green stem as well as new leaf of C. junos under iron stress for two weeks, and the transcripts were accumulated only slightly in P. trifoliata at the same time. The results showed that the obvious increase of FCR activity was an important reason for the tolerance of C. junos to iron_deficiency, and the regulation of FCR activity seemed to be at the transcriptional level, and the expression of FRO2 occurred in the root, stem and leaf.展开更多
Erythropoietic protoporphyria（EPP）, an autosomal dominant disease, is caused by partial deficiency of ferrochelatase（FECH）, which catalyzes the terminal step of heme biosynthesis because of loss-of-function mutati...Erythropoietic protoporphyria（EPP）, an autosomal dominant disease, is caused by partial deficiency of ferrochelatase（FECH）, which catalyzes the terminal step of heme biosynthesis because of loss-of-function mutations in the FECH gene. To date, only a few cases have been described in Asia. In this study, we describe the clinical features of two Chinese patients with EPP, with diagnosis confirmed by the increase of free protoporphyrin in erythrocytes, detection of plasma fluorescence peak at 630–634 nm, and analysis of FECH gene mutations. Using gene scanning, we identified a small deletion in the FECH gene（c.973 delA） in one proband（patient A） and a pathogenic FECH mutation（c.1232 GT） in the other（patient B） and also observed some nucleotide variations（c.798 CG, c.921 AG, IVS1-23 CT, IVS3＋23 AG, IVS9＋35 CT, and IVS3-48 TC） in these patients. The family pedigree of patient A was then established by characterization of the genotype of the patient＇s relatives. We also analyzed the potential perniciousness of the missense mutation with bioinformatic software, Polyphen and Sift. In summary, Chinese EPP patients have similar manifestations to those of Caucasians, and identification of the Chinese FECH gene mutations expands the FECH genotypic spectrum and may contribute to genetic counseling.展开更多
文摘It has been hypothesized that under iron stress high ferric chelate reductase (FCR) activity in the absorptive root of plants tolerant to iron_deficiency will be induced and result in subsequent Fe 2+ transport across the plasmalemma. The activity of FCR and expression of FCR gene (FRO2) in Citrus junos Sieb. ex Tanaka tolerant to iron_deficiency and Poncirus trifoliata (L.) Raf. susceptible to iron_deficiency were determined to elucidate the physiological difference which causes the different tolerance of the two citrus rootstocks to iron stress. The activity of FCR was detectable in excised roots and was stimulated about 20_times in C. junos and only about 3_times in P. trifoliata under iron deficiency for four weeks. The FRO2 of Arabidopsis was used as a probe, the tissue print technique was used to ascertain the expression of the FCR gene in C. junos and P. trifoliata under iron stress. High_level transcripts were observed in the absorptive root, young green stem as well as new leaf of C. junos under iron stress for two weeks, and the transcripts were accumulated only slightly in P. trifoliata at the same time. The results showed that the obvious increase of FCR activity was an important reason for the tolerance of C. junos to iron_deficiency, and the regulation of FCR activity seemed to be at the transcriptional level, and the expression of FRO2 occurred in the root, stem and leaf.
基金supported by the National Basic Research Project(973)of China(No.2012CB934000)the National Distinguished Youth Scholar Grant of China(No.31325010)
文摘Erythropoietic protoporphyria（EPP）, an autosomal dominant disease, is caused by partial deficiency of ferrochelatase（FECH）, which catalyzes the terminal step of heme biosynthesis because of loss-of-function mutations in the FECH gene. To date, only a few cases have been described in Asia. In this study, we describe the clinical features of two Chinese patients with EPP, with diagnosis confirmed by the increase of free protoporphyrin in erythrocytes, detection of plasma fluorescence peak at 630–634 nm, and analysis of FECH gene mutations. Using gene scanning, we identified a small deletion in the FECH gene（c.973 delA） in one proband（patient A） and a pathogenic FECH mutation（c.1232 GT） in the other（patient B） and also observed some nucleotide variations（c.798 CG, c.921 AG, IVS1-23 CT, IVS3＋23 AG, IVS9＋35 CT, and IVS3-48 TC） in these patients. The family pedigree of patient A was then established by characterization of the genotype of the patient＇s relatives. We also analyzed the potential perniciousness of the missense mutation with bioinformatic software, Polyphen and Sift. In summary, Chinese EPP patients have similar manifestations to those of Caucasians, and identification of the Chinese FECH gene mutations expands the FECH genotypic spectrum and may contribute to genetic counseling.
