Objective. To examine the effect of isobutyramide synthesized in our laboratory on human and murine globin gene expression and to test cell toxicity ofthe drug.Methods. MEL cells were transfected with the recombinant ...Objective. To examine the effect of isobutyramide synthesized in our laboratory on human and murine globin gene expression and to test cell toxicity ofthe drug.Methods. MEL cells were transfected with the recombinant construct μLCRAγψβδβand the stable transformants were cultured in the medium with different concentrations of isobutyramide. The experimental mice and rabbit were injected with different doses of isobutyramide. The globin mRNAs were analyzed by RNase protection assay. The hematological toxicity and electrolyte toxicity ofthe drug were tested.Results. An inducible and dose dependent expression of the human γ , β and mouse α globin gene was observed in the transfected MEL cells. The induction of the human γ globin gene is significant stronger than that of the β globin gene. With 2.5～5 mmol/L isobutyramide, the induction of the human γ globin gene is even more effective than that of mouse α globin gene. After a 15 day injection under the doses of 500～900mg·kg-1·d-1, the level of the mouse embryonic εy globin mRNA could be significantly induced up to 3～4 fold of that of uninjected controls. The changes of hemoglobin(Hb), RBC, hematocrit(HCT), WBC, derived from mice injected with different doses of isobutyramide at the interval of 24 hours for 2～4 weeks, were generally within the normal range. In rabbits injected with isobutyramide in the same regiment for 2 weeks, the concentration of blood K+, Na+, Cl-and CO2 were all within normal range and serum ionic osmotic pressure remained stable as well. Conclusion. Our results suggested that isobutyramide is a weak inducer ofcell differentiation, but it can selectively activate transcription of human γ globin gene at a certain degree, and it can act on early stages of erythroid progenitor differentiation in adult mice and activate transcription of embryonic εy-globin gene and have no hematological toxicity. Our results have further proved the potential value of isobutyramide in treatment of β-thalassemia and sickle cell disease.展开更多
Introduction: Beta-thalassemia is characterized by absence or reduced synthesis of the β-globin. Carriers of β-thalas- semia, typically have microcytic hypochromic anemia and elevated hemoglobin HbA2 and normal HbF ...Introduction: Beta-thalassemia is characterized by absence or reduced synthesis of the β-globin. Carriers of β-thalas- semia, typically have microcytic hypochromic anemia and elevated hemoglobin HbA2 and normal HbF level. On the other hand carriers of severe alpha-thalassemia also have similar CBC parameters to that of β-thalassemia with normal HbA2 level. Co-presence of mutations in the β-globin and delta-globin genes (point mutations or deletions) usually give normal HbA2 and elevated HbF level. We report a β-thal carrier with normal level of HbA2 and increased level of HbF who had a point mutation in CD39 on the beta-globin gene and a point mutation in CD27 on the δ-globin gene named Hb-Yialousa. Materials & Methods: An individual with low hematological indices, normal HbA2 and elevated HbF was referred to our center as routine premarital screening program. Mutations in the β-globin and δ-globin genes were screened using ARMS and sequencing methods. Results: The mutation in β- and δ-globin genes were identified as CD39 and CD27 (HbYialousa) respectively. No point mutation or deletion in α-globin gene was identified. Discussion: We showed that normal HBA2 with elevated HbF level is due to co-inheritance of delta-globin gene mutation with mutation in the β-globin gene. When screening for β-thalassemia, one has to either rule out presence of α-globin gene mutation of mutation in the delta-globin gene.展开更多
Hemoglobinopathies, mainly Sickle cell disease (SCD), are the most common monogenic disorders in Africa. In Burkina Faso, data on these diseases are scarce, mainly hospital-based in Ouagadougou and its surroundings. I...Hemoglobinopathies, mainly Sickle cell disease (SCD), are the most common monogenic disorders in Africa. In Burkina Faso, data on these diseases are scarce, mainly hospital-based in Ouagadougou and its surroundings. In order to assess the incidence and allelic frequencies of the main hemoglobinopathies in newborns in Burkina Faso, we conducted a cross-sectional study from 2015 to 2019 in four hospitals. The study included babies of both sexes, regardless of ethnic group and parents’ hemoglobin status. It was a newborn screening and hemoglobin variants were detected using isoelectric focusing on cord blood samples and confirmed using hemoglobin electrophoresis by high-performance liquid chromatography. The proportions and cumulative incidences of the different hemoglobinopathies were computed. Hardy-Weinberg equilibrium law was applied to calculate genotypic and allelic frequencies. The significant level was p < 0.05. Out of 11,337 newborns included, 47.8% were males and 60.2% were from Bobo-Dioulasso. Abnormal hemoglobin was found in 27.1%, representing a cumulative incidence of 1:4 newborns. The incidence of SCD was 1.9% (1:53 newborns) with 27.9% of homozygous SS. Homozygous CC and compound heterozygous Cβ-Thalassemia accounted for 1.1%. SCD cases were 1.51 times higher in Bobo-Dioulasso (OR = 1.51;95% CI [1.09 - 2.10]: p = 0.013). The observed genotype frequencies were significantly different from the expected ones (p 0.001). The βS and βC alleles represented 5.1 and 9.9%, respectively. This study showed a high incidence of hemoglobinopathies. Such results raise the question of control strategies for these hemoglobinopathies in our country.展开更多
One adult α-globin gene and one β-globin gene have been cloned from the large yellow croaker Pseudosciaena crocea. Linkage analysis indicated that the α- and β-globin genes were oriented head-to-head relative to e...One adult α-globin gene and one β-globin gene have been cloned from the large yellow croaker Pseudosciaena crocea. Linkage analysis indicated that the α- and β-globin genes were oriented head-to-head relative to each other. To identify the regulatory elements present in the intergenic and intragenic regions of the globin complex, the intergenic region alone or together with the β-globin gene first intron was cloned into the luciferase-reporter vector pGL3-Basic respectively, and the chimeric constructs were tran- siently transfected into Vero cells and primary fish erythrocytes. The intergenic region cannot support the high-level expression of luciferase. However, the promoter activity of the intergenic region was strongly stimulated by the positive regulatory elements （PRE） located in the β-globin gene intron 1. Thus, it is proposed that the intergenic promoters and intragenic PRE were necessary for the effective expression of the linked α- and β-globin genes.展开更多
EKLF is an erythroid-specific, zinc finger-containing transcription factor essential for the activation of the mammalian beta globin gene in erythroid cells of definitive lineage. We have prepared a polyclonal anti-mo...EKLF is an erythroid-specific, zinc finger-containing transcription factor essential for the activation of the mammalian beta globin gene in erythroid cells of definitive lineage. We have prepared a polyclonal anti-mouse EKLF antibody suitable for Western blotting and immunoprecipitation （IP） qualities, and used it to define the expression patterns of the EKLF protein during mouse erythroid development. We have also used this antibody for the chromatin-immunoprecipitation （CHIP） assay. EKLF was found to bind in vivo at both the mouse beta-major-globin promoter and the HS2 site of beta-LCR in the mouse erythroleukemia cells （MEL） in a DMSO-inducible manner. The DMSO-induced bindings of EKLF as well as three other proteins, namely, RNA polymerase Ⅱ, acetylated histone H3, and methylated histone H3, were not abolished but significantly lowered in CB3, a MEL-derived cell line with null-expression of p45/NF-E2, an erythroid-enriched factor needed for activation of the mammalian globin loci. Interestingly, binding of EKLF in vivo was also detected in the mouse alpha-like globin locus, at the adult alpha globin promoter and its far upstream regulatory element alpha-MRE （HS26）. This study provides direct evidence for EKLF-binding in vivo at the major regulatory elements of the mouse beta-like globin gene clusters the data also have interesting implications with respect to the role of EKLF-chromatin interaction in mammalian globin gene regulation.展开更多
The α- and β-globin genes from Pseudosciaena crocea were cloned by rapid amplification of cDNA 3 ＇-end （ 3 ＇-RACE）. The cDNA of the α-globin is 595 bp with the ATG start codon located at Position 37, the TAA st...The α- and β-globin genes from Pseudosciaena crocea were cloned by rapid amplification of cDNA 3 ＇-end （ 3 ＇-RACE）. The cDNA of the α-globin is 595 bp with the ATG start codon located at Position 37, the TAA stop codon at Position 469 and the AATAAA polyadenylation signal at Position 560, which codifies 145 amino acids. The entire open reading frame of the β-globin gene is 447 bp long, which encodes 148 amino acids. Amino acid identity of the α- globin or β-globin gene compared with those reported in other fish species, ranged from 31.9% to 76.4%. When comparing with human α- and β-globins, three important alterations in the structural regions can be noted： ct39 Thr→Gln, α113 His→Tyr and β117 His→Lys. The α-globin has a unique inserted amino acid residue in the 47th position. To understand the process of globin gene duplication and identify the regulatory elements present in the intergenic and intragenic regions of globin genes, the genomic arrangement of α- and β-globin genes was investigated. The results showed that the orientation of the two genes was head-to-head relative to each other. The intergenic region between the translation initiation codons of the linked α- and β-globin genes contains classical promoter elements and the length of it is much shorter than that reported in other fish.展开更多
A cosmid construct μLCRAγψβδβ were induced into mouse erythroleukemia cell lines 585 that expresses murine adult globin only and MEL GM 979 that expresses both murine embryonic and ad...A cosmid construct μLCRAγψβδβ were induced into mouse erythroleukemia cell lines 585 that expresses murine adult globin only and MEL GM 979 that expresses both murine embryonic and adult globins.Similar patterns of human globin gene expression were displayed in the two MEL cell lines transfected with the construct.Inducible expression of the Aγ and β gene was observed during induced cell differentiation.However,the expression level of the Aγ globin gene is much higher than that of the β globin gene in either uninduced or induced MEL transformants.No γ to β switching happened in the stable MEL transformants following a continuous culture.The much more effective enhance of the μLCR on the Aγ globin gene than that on the β globin gene is resulted probably from the fact that the distance between the LCR and the β globin gene is much longer than that between the LCR and the Aγ globin gene in the construct,in comparison with other constructs containing HS2 or μLCR linked to both of γ and β globin genes in different order.Two suggestions can be derived from these results:1) A competition between the γ and β globin gene for interaction with the LCR may indeed present,but only an enough long distance difference between the LCR to the γ and to the β gene can effectively influence the competition;2) Unlike transgenic mice,MEL cells are incapable of reconstructing the regulatory information involved in developmental control when it is provided by a fragment of the β globin gene cluster with limited length.展开更多
Seventy-four members from 9 adult polycystic kidney disease(APKD)familieswere analysed with Southern blot and 3′hypervariable region/Pvu Ⅱ,3′HVR/Bgl ⅡRFLPs.The results showed that 3′ HVR fragments were highly pol...Seventy-four members from 9 adult polycystic kidney disease(APKD)familieswere analysed with Southern blot and 3′hypervariable region/Pvu Ⅱ,3′HVR/Bgl ⅡRFLPs.The results showed that 3′ HVR fragments were highly polymorphic.Theheterozygote frequencies of Pvu Ⅱ,Bgl Ⅱ and PvuⅡ+Bg1Ⅱ fragments were 92%,84.7%and 98.6%,respectively.The maximum lod score for linkage between 3′HVR and APKDwas 9.71 at a recombination fraction 0.045.We successfully applied 3′HVR probe to thegene diagnosis of 17 symptomatic patients and 7 patients in the presymptomatic stage.展开更多
Retroviral mediated gene transfer of humanglobin gene into hematopoietic stem cells is apromising approach for thalassemia gene therapy.Major problem of the transferred globin gene was lowlevel expression of the gene ...Retroviral mediated gene transfer of humanglobin gene into hematopoietic stem cells is apromising approach for thalassemia gene therapy.Major problem of the transferred globin gene was lowlevel expression of the gene with its proximal cis-acting sequence. The locus control region (LCR) ofthe human β-globin gene cluster consists of four majorDNase I hypersensitive sites (HS). When linked展开更多
OBJECTIVE: To further characterize the differentiation inducing properties of EDRF1 and demonstrate its functional pathway involved in regulation of globin gene expression. METHODS: By transfecting EDRF1 sense and ant...OBJECTIVE: To further characterize the differentiation inducing properties of EDRF1 and demonstrate its functional pathway involved in regulation of globin gene expression. METHODS: By transfecting EDRF1 sense and antisense constructs into HEL cells, we identified the expression of globin and erythropoietin receptor genes by Northern blot analysis. RT-PCR and EMSA (electrophoresis mobility shift assay) were performed to monitor the expression and DNA-binding activity of erythroid specific transcription factors GATA-1 and NF-E2. RESULTS: It was shown that when EDRF1 was overexpressed, production of alpha-globin increased. In antisense EDRF1, overexpression of HEL cells, significant loss of alpha-, gamma-globin mRNA synthesis was observed. The transcription of endogenous GATA-1 and NF-E2 mRNA expression were maintained at the same levels compared with control experiments. However, the transcription activity of GATA-1 was severely impaired. Expression of erythropoietin receptor gene was not influenced by EDRF1 gene overexpression. CONCLUSION: The results suggested that EDRF1 regulated alpha- and gamma-globin gene synthesis by modulating DNA-binding activity of GATA-1 transcription factor.展开更多
Mycophenolic acid(MPA,1)and its derivatives are first-line immunosuppressants used in organ transplantation and for treating autoimmune diseases.Despite chemical synthetic achievements,the biosynthetic formation of a ...Mycophenolic acid(MPA,1)and its derivatives are first-line immunosuppressants used in organ transplantation and for treating autoimmune diseases.Despite chemical synthetic achievements,the biosynthetic formation of a seven-carbon carboxylic acid pharmacophore side chain of 1,especially the processes involving the cleavage of the prenyl side chain between DHMP(4)and DMMPA(5),remains unknown.In this work,we identified a membrane-bound prenyltransferase,PgMpaA,that transfers FPP to 4 to yield FDHMP(6).Compound 6 undergoes the first cleavage step via a new globin-like enzyme PgMpaB to form a cryptic intermediate 12.Heterologous expression of PgMpa genes in Aspergillus nidulans demonstrates that the second cleavage step(from 12 to 5)of 1 is a PgMpa clusterindependent process in vivo.Our results,especially the discovery of the broad tolerance of substrates recognized by PgMpaB,set up a strategy for the formation of"pseudo-isopentenyl"natural products using fungal globin-like enzymes.展开更多
A newly developed method of RT-PCR/competitive PCR for measuring the relative and ab-solute content of globin mRNAs as well as micro-globin chain biosynthetic assay have been used to study thealterations of globin gen...A newly developed method of RT-PCR/competitive PCR for measuring the relative and ab-solute content of globin mRNAs as well as micro-globin chain biosynthetic assay have been used to study thealterations of globin gene expressions in the patients with β-thalassemia pre-and post-hydroxyurea(HU)treatment.It was found for the first time that HU had the effect of enhancing β-globin gene expression insome patients.Two cases with β-thalassemia who were subjected to HU treatment for over two years showeda marked increase in β-globin mRNA level and β-globin chain synthesis,resulting in more effective erythro-poiesis and the alleviation of clinical symptoms.展开更多
The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-...The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-8th weeks of gestation. Recently, several studieson the transgenic mice have shown that the 5′-flanking DNA sequences of human展开更多
By electrophoretic mobility shift assay (EMSA), the effect of point mutation C→T at - 64 of human δ-globin gene on its binding proteins has been studied. Two segments of 36 bp from - 83- - 48 bp of the 6 globin gene...By electrophoretic mobility shift assay (EMSA), the effect of point mutation C→T at - 64 of human δ-globin gene on its binding proteins has been studied. Two segments of 36 bp from - 83- - 48 bp of the 6 globin gene promoter, named WOG and MOG, were synthesized. WOG includes wild type CAAT-like box (CCAAC), while MOG includes the mutant CAAT-like box (CCAAT, -64 C→T). Results indicate that: ( i ) in erythroid cell lines MEL, K562 and Hemin induced K562, the affinity of MOG with CCAAT binding protein (CBF) and GATA-1展开更多
In previous studies, we found that EDRF2 was an erythroid differentiation related factor, whose expression was markedly upregulated during erythroid differentiation. It suggested that this factor played a role in eryt...In previous studies, we found that EDRF2 was an erythroid differentiation related factor, whose expression was markedly upregulated during erythroid differentiation. It suggested that this factor played a role in erythropoiesis. By using rapid amplification of cDNA ends technology, we cloned EDRF2 gene 5’-and 3’-cDNA ends successfully. Transfection and Northern blot analysis demonstrated that EDRF2 inhibited mRNA expression of a-globin gene, while did not regulate γ-globin gene expression. Gel shift assay confirmed that DNA-binding activity of erythroid specific transcription factors GATA-1, NF-E2 and AP1 was not affected by either forced overexpression or artificial down-regulation of EDRF2 gene in K562 cells. However, we detected that the negative regulator of expression of GATA-1 transcription factor was increased in EDRF2 overexpressed K562 cells. These results strongly suggested that EDRF2 was involved in a-globin gene expression and erythroid differentiation and served as a negative regulator of展开更多
HMG proteins are abundant chromosomal non-histone proteins. It has been suggested that the HMG proteins may play an important role in the structure and function of chromatin. In the present study, the binding of HMG p...HMG proteins are abundant chromosomal non-histone proteins. It has been suggested that the HMG proteins may play an important role in the structure and function of chromatin. In the present study, the binding of HMG proteins (HMG1/2 and HMG14/17) to the core DNA sequence of DNasel hypersensitive site 2 (HS2core DNA sequence, -10681-10970 bp) in the locus control region (LCR) of the human β-like globin gene cluster has been examined by using both the in vitro nucleosome reconstitution and the gel mobility shift assays. Here we show that HMG1/2 can bind to the naked HS2core DNA sequence, however, HMG 14/17 cannot. Using the in vitro nucleosome reconstitution we demonstrate that HMG14/17 can bind to the HS2core DNA sequence which is assembled into nucleosomes with the core histone octamer transferred from chicken erythrocytes. In contrast, HMG 1/2 cannot bind to the nucleosomes reconstituted in vitro with the HS2core DNA sequence. These results indicate that the binding patterns between HMG proteins and the HS2core DNA sequence which exists in different states (the naked DNA or the in vitro reconstituted nucleosomal DNA) are quite different. We speculate that HMG proteins might play a critical role in the regulation of the human β-like globin gene's expression.展开更多
The polymorphism of human globin genes as a genetic marker has been widely used in studies related to anthropology, genetics and prenatal diagnosis of genetic diseases (e.g. prenatal diagnosis of β-thalassemia and si...The polymorphism of human globin genes as a genetic marker has been widely used in studies related to anthropology, genetics and prenatal diagnosis of genetic diseases (e.g. prenatal diagnosis of β-thalassemia and sickle cell anemia). Since 1978, several polymorphic restriction endonuclease sites in the human in β-globin gene cluster展开更多
文摘Objective. To examine the effect of isobutyramide synthesized in our laboratory on human and murine globin gene expression and to test cell toxicity ofthe drug.Methods. MEL cells were transfected with the recombinant construct μLCRAγψβδβand the stable transformants were cultured in the medium with different concentrations of isobutyramide. The experimental mice and rabbit were injected with different doses of isobutyramide. The globin mRNAs were analyzed by RNase protection assay. The hematological toxicity and electrolyte toxicity ofthe drug were tested.Results. An inducible and dose dependent expression of the human γ , β and mouse α globin gene was observed in the transfected MEL cells. The induction of the human γ globin gene is significant stronger than that of the β globin gene. With 2.5～5 mmol/L isobutyramide, the induction of the human γ globin gene is even more effective than that of mouse α globin gene. After a 15 day injection under the doses of 500～900mg·kg-1·d-1, the level of the mouse embryonic εy globin mRNA could be significantly induced up to 3～4 fold of that of uninjected controls. The changes of hemoglobin(Hb), RBC, hematocrit(HCT), WBC, derived from mice injected with different doses of isobutyramide at the interval of 24 hours for 2～4 weeks, were generally within the normal range. In rabbits injected with isobutyramide in the same regiment for 2 weeks, the concentration of blood K+, Na+, Cl-and CO2 were all within normal range and serum ionic osmotic pressure remained stable as well. Conclusion. Our results suggested that isobutyramide is a weak inducer ofcell differentiation, but it can selectively activate transcription of human γ globin gene at a certain degree, and it can act on early stages of erythroid progenitor differentiation in adult mice and activate transcription of embryonic εy-globin gene and have no hematological toxicity. Our results have further proved the potential value of isobutyramide in treatment of β-thalassemia and sickle cell disease.
文摘Introduction: Beta-thalassemia is characterized by absence or reduced synthesis of the β-globin. Carriers of β-thalas- semia, typically have microcytic hypochromic anemia and elevated hemoglobin HbA2 and normal HbF level. On the other hand carriers of severe alpha-thalassemia also have similar CBC parameters to that of β-thalassemia with normal HbA2 level. Co-presence of mutations in the β-globin and delta-globin genes (point mutations or deletions) usually give normal HbA2 and elevated HbF level. We report a β-thal carrier with normal level of HbA2 and increased level of HbF who had a point mutation in CD39 on the beta-globin gene and a point mutation in CD27 on the δ-globin gene named Hb-Yialousa. Materials & Methods: An individual with low hematological indices, normal HbA2 and elevated HbF was referred to our center as routine premarital screening program. Mutations in the β-globin and δ-globin genes were screened using ARMS and sequencing methods. Results: The mutation in β- and δ-globin genes were identified as CD39 and CD27 (HbYialousa) respectively. No point mutation or deletion in α-globin gene was identified. Discussion: We showed that normal HBA2 with elevated HbF level is due to co-inheritance of delta-globin gene mutation with mutation in the β-globin gene. When screening for β-thalassemia, one has to either rule out presence of α-globin gene mutation of mutation in the delta-globin gene.
文摘Hemoglobinopathies, mainly Sickle cell disease (SCD), are the most common monogenic disorders in Africa. In Burkina Faso, data on these diseases are scarce, mainly hospital-based in Ouagadougou and its surroundings. In order to assess the incidence and allelic frequencies of the main hemoglobinopathies in newborns in Burkina Faso, we conducted a cross-sectional study from 2015 to 2019 in four hospitals. The study included babies of both sexes, regardless of ethnic group and parents’ hemoglobin status. It was a newborn screening and hemoglobin variants were detected using isoelectric focusing on cord blood samples and confirmed using hemoglobin electrophoresis by high-performance liquid chromatography. The proportions and cumulative incidences of the different hemoglobinopathies were computed. Hardy-Weinberg equilibrium law was applied to calculate genotypic and allelic frequencies. The significant level was p < 0.05. Out of 11,337 newborns included, 47.8% were males and 60.2% were from Bobo-Dioulasso. Abnormal hemoglobin was found in 27.1%, representing a cumulative incidence of 1:4 newborns. The incidence of SCD was 1.9% (1:53 newborns) with 27.9% of homozygous SS. Homozygous CC and compound heterozygous Cβ-Thalassemia accounted for 1.1%. SCD cases were 1.51 times higher in Bobo-Dioulasso (OR = 1.51;95% CI [1.09 - 2.10]: p = 0.013). The observed genotype frequencies were significantly different from the expected ones (p 0.001). The βS and βC alleles represented 5.1 and 9.9%, respectively. This study showed a high incidence of hemoglobinopathies. Such results raise the question of control strategies for these hemoglobinopathies in our country.
基金The National Natural Science Foundation of China under contract Nos 30640015 and 30771644the Major Program of Zhejiang Province of China under contract No. 2005C23085
文摘One adult α-globin gene and one β-globin gene have been cloned from the large yellow croaker Pseudosciaena crocea. Linkage analysis indicated that the α- and β-globin genes were oriented head-to-head relative to each other. To identify the regulatory elements present in the intergenic and intragenic regions of the globin complex, the intergenic region alone or together with the β-globin gene first intron was cloned into the luciferase-reporter vector pGL3-Basic respectively, and the chimeric constructs were tran- siently transfected into Vero cells and primary fish erythrocytes. The intergenic region cannot support the high-level expression of luciferase. However, the promoter activity of the intergenic region was strongly stimulated by the positive regulatory elements （PRE） located in the β-globin gene intron 1. Thus, it is proposed that the intergenic promoters and intragenic PRE were necessary for the effective expression of the linked α- and β-globin genes.
文摘EKLF is an erythroid-specific, zinc finger-containing transcription factor essential for the activation of the mammalian beta globin gene in erythroid cells of definitive lineage. We have prepared a polyclonal anti-mouse EKLF antibody suitable for Western blotting and immunoprecipitation （IP） qualities, and used it to define the expression patterns of the EKLF protein during mouse erythroid development. We have also used this antibody for the chromatin-immunoprecipitation （CHIP） assay. EKLF was found to bind in vivo at both the mouse beta-major-globin promoter and the HS2 site of beta-LCR in the mouse erythroleukemia cells （MEL） in a DMSO-inducible manner. The DMSO-induced bindings of EKLF as well as three other proteins, namely, RNA polymerase Ⅱ, acetylated histone H3, and methylated histone H3, were not abolished but significantly lowered in CB3, a MEL-derived cell line with null-expression of p45/NF-E2, an erythroid-enriched factor needed for activation of the mammalian globin loci. Interestingly, binding of EKLF in vivo was also detected in the mouse alpha-like globin locus, at the adult alpha globin promoter and its far upstream regulatory element alpha-MRE （HS26）. This study provides direct evidence for EKLF-binding in vivo at the major regulatory elements of the mouse beta-like globin gene clusters the data also have interesting implications with respect to the role of EKLF-chromatin interaction in mammalian globin gene regulation.
基金supported by a grant from a major program of Zhejiang Province Commission of Science and Technologythe National Natural Science Foundation of China under contract No.2005C23085.
文摘The α- and β-globin genes from Pseudosciaena crocea were cloned by rapid amplification of cDNA 3 ＇-end （ 3 ＇-RACE）. The cDNA of the α-globin is 595 bp with the ATG start codon located at Position 37, the TAA stop codon at Position 469 and the AATAAA polyadenylation signal at Position 560, which codifies 145 amino acids. The entire open reading frame of the β-globin gene is 447 bp long, which encodes 148 amino acids. Amino acid identity of the α- globin or β-globin gene compared with those reported in other fish species, ranged from 31.9% to 76.4%. When comparing with human α- and β-globins, three important alterations in the structural regions can be noted： ct39 Thr→Gln, α113 His→Tyr and β117 His→Lys. The α-globin has a unique inserted amino acid residue in the 47th position. To understand the process of globin gene duplication and identify the regulatory elements present in the intergenic and intragenic regions of globin genes, the genomic arrangement of α- and β-globin genes was investigated. The results showed that the orientation of the two genes was head-to-head relative to each other. The intergenic region between the translation initiation codons of the linked α- and β-globin genes contains classical promoter elements and the length of it is much shorter than that reported in other fish.
文摘A cosmid construct μLCRAγψβδβ were induced into mouse erythroleukemia cell lines 585 that expresses murine adult globin only and MEL GM 979 that expresses both murine embryonic and adult globins.Similar patterns of human globin gene expression were displayed in the two MEL cell lines transfected with the construct.Inducible expression of the Aγ and β gene was observed during induced cell differentiation.However,the expression level of the Aγ globin gene is much higher than that of the β globin gene in either uninduced or induced MEL transformants.No γ to β switching happened in the stable MEL transformants following a continuous culture.The much more effective enhance of the μLCR on the Aγ globin gene than that on the β globin gene is resulted probably from the fact that the distance between the LCR and the β globin gene is much longer than that between the LCR and the Aγ globin gene in the construct,in comparison with other constructs containing HS2 or μLCR linked to both of γ and β globin genes in different order.Two suggestions can be derived from these results:1) A competition between the γ and β globin gene for interaction with the LCR may indeed present,but only an enough long distance difference between the LCR to the γ and to the β gene can effectively influence the competition;2) Unlike transgenic mice,MEL cells are incapable of reconstructing the regulatory information involved in developmental control when it is provided by a fragment of the β globin gene cluster with limited length.
文摘Seventy-four members from 9 adult polycystic kidney disease(APKD)familieswere analysed with Southern blot and 3′hypervariable region/Pvu Ⅱ,3′HVR/Bgl ⅡRFLPs.The results showed that 3′ HVR fragments were highly polymorphic.Theheterozygote frequencies of Pvu Ⅱ,Bgl Ⅱ and PvuⅡ+Bg1Ⅱ fragments were 92%,84.7%and 98.6%,respectively.The maximum lod score for linkage between 3′HVR and APKDwas 9.71 at a recombination fraction 0.045.We successfully applied 3′HVR probe to thegene diagnosis of 17 symptomatic patients and 7 patients in the presymptomatic stage.
文摘Retroviral mediated gene transfer of humanglobin gene into hematopoietic stem cells is apromising approach for thalassemia gene therapy.Major problem of the transferred globin gene was lowlevel expression of the gene with its proximal cis-acting sequence. The locus control region (LCR) ofthe human β-globin gene cluster consists of four majorDNase I hypersensitive sites (HS). When linked
文摘OBJECTIVE: To further characterize the differentiation inducing properties of EDRF1 and demonstrate its functional pathway involved in regulation of globin gene expression. METHODS: By transfecting EDRF1 sense and antisense constructs into HEL cells, we identified the expression of globin and erythropoietin receptor genes by Northern blot analysis. RT-PCR and EMSA (electrophoresis mobility shift assay) were performed to monitor the expression and DNA-binding activity of erythroid specific transcription factors GATA-1 and NF-E2. RESULTS: It was shown that when EDRF1 was overexpressed, production of alpha-globin increased. In antisense EDRF1, overexpression of HEL cells, significant loss of alpha-, gamma-globin mRNA synthesis was observed. The transcription of endogenous GATA-1 and NF-E2 mRNA expression were maintained at the same levels compared with control experiments. However, the transcription activity of GATA-1 was severely impaired. Expression of erythropoietin receptor gene was not influenced by EDRF1 gene overexpression. CONCLUSION: The results suggested that EDRF1 regulated alpha- and gamma-globin gene synthesis by modulating DNA-binding activity of GATA-1 transcription factor.
基金supported by the National Natural Science Foundation of China(31870022)the Fundamental Research Funds for the Central Universities(XDJK2018B035 and 201941001,China)+3 种基金the Scientific Research Starting Foundation of Southwest University(SWU117034,China)the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao,China)(No.2018SDKJ0401-2)Taishan Scholar Youth Expert Program in Shandong Province(tsqn201812021,China)supported by the Venture&Innovation Support Program for Chongqing Overseas Returnees and the Thousand Young Talents Program of China.
文摘Mycophenolic acid(MPA,1)and its derivatives are first-line immunosuppressants used in organ transplantation and for treating autoimmune diseases.Despite chemical synthetic achievements,the biosynthetic formation of a seven-carbon carboxylic acid pharmacophore side chain of 1,especially the processes involving the cleavage of the prenyl side chain between DHMP(4)and DMMPA(5),remains unknown.In this work,we identified a membrane-bound prenyltransferase,PgMpaA,that transfers FPP to 4 to yield FDHMP(6).Compound 6 undergoes the first cleavage step via a new globin-like enzyme PgMpaB to form a cryptic intermediate 12.Heterologous expression of PgMpa genes in Aspergillus nidulans demonstrates that the second cleavage step(from 12 to 5)of 1 is a PgMpa clusterindependent process in vivo.Our results,especially the discovery of the broad tolerance of substrates recognized by PgMpaB,set up a strategy for the formation of"pseudo-isopentenyl"natural products using fungal globin-like enzymes.
基金the Chinese"863"Research Grant and NIH Grant HLB-29623
文摘A newly developed method of RT-PCR/competitive PCR for measuring the relative and ab-solute content of globin mRNAs as well as micro-globin chain biosynthetic assay have been used to study thealterations of globin gene expressions in the patients with β-thalassemia pre-and post-hydroxyurea(HU)treatment.It was found for the first time that HU had the effect of enhancing β-globin gene expression insome patients.Two cases with β-thalassemia who were subjected to HU treatment for over two years showeda marked increase in β-globin mRNA level and β-globin chain synthesis,resulting in more effective erythro-poiesis and the alleviation of clinical symptoms.
基金Project supported by grants from Shanghai Joint Laboratory of Life Sciences, the Chinese Academy of Sciences, and the National Natural Science Foundation of China.
文摘The human ε-globin gene is expressed in a tissue-specific and developmental stage-specific manner. During the earliest stage of gestation, this gene is expressed in the yolksac, but is silenced completely at the 6th-8th weeks of gestation. Recently, several studieson the transgenic mice have shown that the 5′-flanking DNA sequences of human
文摘By electrophoretic mobility shift assay (EMSA), the effect of point mutation C→T at - 64 of human δ-globin gene on its binding proteins has been studied. Two segments of 36 bp from - 83- - 48 bp of the 6 globin gene promoter, named WOG and MOG, were synthesized. WOG includes wild type CAAT-like box (CCAAC), while MOG includes the mutant CAAT-like box (CCAAT, -64 C→T). Results indicate that: ( i ) in erythroid cell lines MEL, K562 and Hemin induced K562, the affinity of MOG with CCAAT binding protein (CBF) and GATA-1
文摘In previous studies, we found that EDRF2 was an erythroid differentiation related factor, whose expression was markedly upregulated during erythroid differentiation. It suggested that this factor played a role in erythropoiesis. By using rapid amplification of cDNA ends technology, we cloned EDRF2 gene 5’-and 3’-cDNA ends successfully. Transfection and Northern blot analysis demonstrated that EDRF2 inhibited mRNA expression of a-globin gene, while did not regulate γ-globin gene expression. Gel shift assay confirmed that DNA-binding activity of erythroid specific transcription factors GATA-1, NF-E2 and AP1 was not affected by either forced overexpression or artificial down-regulation of EDRF2 gene in K562 cells. However, we detected that the negative regulator of expression of GATA-1 transcription factor was increased in EDRF2 overexpressed K562 cells. These results strongly suggested that EDRF2 was involved in a-globin gene expression and erythroid differentiation and served as a negative regulator of
文摘HMG proteins are abundant chromosomal non-histone proteins. It has been suggested that the HMG proteins may play an important role in the structure and function of chromatin. In the present study, the binding of HMG proteins (HMG1/2 and HMG14/17) to the core DNA sequence of DNasel hypersensitive site 2 (HS2core DNA sequence, -10681-10970 bp) in the locus control region (LCR) of the human β-like globin gene cluster has been examined by using both the in vitro nucleosome reconstitution and the gel mobility shift assays. Here we show that HMG1/2 can bind to the naked HS2core DNA sequence, however, HMG 14/17 cannot. Using the in vitro nucleosome reconstitution we demonstrate that HMG14/17 can bind to the HS2core DNA sequence which is assembled into nucleosomes with the core histone octamer transferred from chicken erythrocytes. In contrast, HMG 1/2 cannot bind to the nucleosomes reconstituted in vitro with the HS2core DNA sequence. These results indicate that the binding patterns between HMG proteins and the HS2core DNA sequence which exists in different states (the naked DNA or the in vitro reconstituted nucleosomal DNA) are quite different. We speculate that HMG proteins might play a critical role in the regulation of the human β-like globin gene's expression.
文摘The polymorphism of human globin genes as a genetic marker has been widely used in studies related to anthropology, genetics and prenatal diagnosis of genetic diseases (e.g. prenatal diagnosis of β-thalassemia and sickle cell anemia). Since 1978, several polymorphic restriction endonuclease sites in the human in β-globin gene cluster
