The DNasel hypersensitive site 2 (HS2) of human β-globin locus control region (LCR) is required fOr the high level expression of human d-globin genes. In the present study, a stage-specific protein factor (LPF-β) wa...The DNasel hypersensitive site 2 (HS2) of human β-globin locus control region (LCR) is required fOr the high level expression of human d-globin genes. In the present study, a stage-specific protein factor (LPF-β) was identified in the nuclear extract prepared from mouse fetal liver at d 18 of gestation, which could bind to the HS2 region of humanβ-globin LCRt We also found that the shift band of LPF-βfactor could be competed by humanβ-globin promoter. However, it couldn’t be competed by human E-globin promoter or by human Aβ-globin promoter. Furthermore, our data demonstrated that the binding-sequence of LPF-d factor is 5’CACACCCTA 3’,which is located at the HS2 region ofβ-LCR (from -10845 to -10853 bp) and humanβ-globin promoter (from -92 to -84 bp). We speculated that these regions containing the CACCC box in both the humallβ-globin promoter and HS2 might function as stage selector elements in the regulation of humanβd-globin switching and the LPF-βfactor might be a stage-specific protein factor involved in the regulation of humanβ-globin gene expression.展开更多
In order to elucidate the molecular mechanisms of globin gene expression during embryonic development, the nuclear extracts from mouse hematopoietic tissue at different stages of development have been prepared. By usi...In order to elucidate the molecular mechanisms of globin gene expression during embryonic development, the nuclear extracts from mouse hematopoietic tissue at different stages of development have been prepared. By using DNase I footprinting and gel mobility shift assays, the binding of protein factors in these extracts to the human βglobin promoter was analyzed. The differences in the binding patterns of protein factors during development were observed. An erythroid-specific and stage-specific nuclear protein in the nuclear extract from d 18 mouse fetal liver was identified, which can bind to the sequence (from -66bp to -90bp) of human β-globin promoter. We therefore speculate that the function of this cis-acting element may be similar to stage selector element (SSE) in chieken βA- promoter.展开更多
Objective:Studies have shown thatβ-globin gene presents a selective expression transformation mechanism during development,and its upstream locus control region(LCR)regulates the expression pattern ofβ-globin gene f...Objective:Studies have shown thatβ-globin gene presents a selective expression transformation mechanism during development,and its upstream locus control region(LCR)regulates the expression pattern ofβ-globin gene family.To further explore the molecular network ofβ-globin gene expression regulation,other long-range regulatory elements that may be involved in the regulation ofβ-globin gene expression were screened and the dynamic regulation and transformation mechanism ofβ-globin gene was deeply studied.Methods:Promyelocytic cells were induced to differentiate by all-trans retinoic acid.β-globin gene promoter region and LCR were used as the target sites for circular chromosome conformational capture(4C)analysis.Through sequencing and regulatory element analysis,the sites interacting withβ-globin family loci were screened in the whole genome.Results:According to the results of 4C sequencing,the sites that interact with HBD promoter region and LCR were screened.Verified by chromosome conformational capture(3C),the results were consistent with those of sequencing.The functional analysis of regulatory elements by formaldehyde-assisted separation regulatory elements and Epiregio online website showed that the screening sites AC105129.4,AL354707.17,AC078785.22 and AC021646.35 were all potential regulatory elements involved inβ-globin gene.Conclusion:The interaction between 4C screening site and anchor site showed the complex spatial organization ofβ-globin family loci in the nucleus.展开更多
Hematopoietic stem cell transplantation(HSCT)has emerged as a curative strategy for sickle cell anemia(SCA);it is necessary to find markers of SCA clinical severity to spare those SCA patients whose clinical course is...Hematopoietic stem cell transplantation(HSCT)has emerged as a curative strategy for sickle cell anemia(SCA);it is necessary to find markers of SCA clinical severity to spare those SCA patients whose clinical course is mild from the morbidity and mortality associated with HSCT. Haplotypes have been correlated with the severity of clinical manifestations in SCA patients, and fetal hemoglobin(HbF)and socioeconomic status(SeS)have also been described as negative factors. We studied these factors and their impact on clinical manifestations in a population of Southern Brazilian patients attending the Center for Sickle Cell Anemia at Hospital de Clínicas de Porto Alegre/RS, Brazil. Clinical severity was defined as two or more veno-occlusive episodes per year. The βS haplotypes were determined by PCR in 75 SCA patients. Among the 150 βS chromosomes analyzed, 99(66%)were identified as Bantu(Ban), 41(27%)asBenin(Ben), and 10(7%)as other haplotypes. Most patients in our sample(62.7%)belonged to lower SeS groups, precluding meaningful statistical analysis of SeS impact on clinical severity. There was no correlation between haplotypes or HbF level and SCA clinical severity. Gene polymorphisms and environmental issues have to be taken into consideration.展开更多
One of the crucial tasks of fundamental studies on modern biology is to explore the regulatory mechanisms of gene expression. Yet so far little has been known about the fine structural changes induced by the interacti...One of the crucial tasks of fundamental studies on modern biology is to explore the regulatory mechanisms of gene expression. Yet so far little has been known about the fine structural changes induced by the interaction between the DNA and the proteins. The major obstacles arise from the fact that it is not easy to crystallize the protein-DNA complex that is generally small in amount. This prevents researchers from gaining knowledge of the local structure with X-ray crystallography. On the other hand, the resolution of the electron microscope is not high enough to reveal structural details in nanometer scale.展开更多
Human β-globin gene family provides an ideal model for studying the expression and regulation of eukaryotic gene. The five transcriptional active genes arranged 5′ε-~Gγ-~Aγ-δ-β 3′ in the order that they are ex...Human β-globin gene family provides an ideal model for studying the expression and regulation of eukaryotic gene. The five transcriptional active genes arranged 5′ε-~Gγ-~Aγ-δ-β 3′ in the order that they are expressed during development. However, the molecular regulatory mechanism of the human globin gene expression remains to be defined. β-globin gene normally expressed in the adult bone marrow, but not in the embryonic stage, which展开更多
The pattern of high mobility group proteins 1 and 2 (HMG1,2) interaction with the 5’-flanking sequence of the human β-globin gene has been analyzed by scanning tunnelling microscopy (STM). A 200 bp negative regulato...The pattern of high mobility group proteins 1 and 2 (HMG1,2) interaction with the 5’-flanking sequence of the human β-globin gene has been analyzed by scanning tunnelling microscopy (STM). A 200 bp negative regulatory region in the 5’-flanking sequence of the human β-globin gene can be folded by HMG proteins 1 and 2 into a circular structure (diameter 70±6) with a linear tail which seems to be a left-handed double helix structure.展开更多
Our previous studies have identified that there are at least three regulatory regions (two negative regions and one positive region) in the 5'-flanking sequence of human β-globin gene (-610 to +1 bp). The binding...Our previous studies have identified that there are at least three regulatory regions (two negative regions and one positive region) in the 5'-flanking sequence of human β-globin gene (-610 to +1 bp). The binding of HMG proteins to both negative regulatory regions was examined by the gel mobility shift and DNase I protection assays.In gel mobility shift assay,we observed that HMG proteins 1 and 2 could bind to both negative regulatory regions (NCR1 and NCR2).Using the gel shift competition assay,we identified that the binding proteins between the two regions are different from each other.DNase I protection analysis shows that HMG proteins 1 and 2 only bind to one site (between-560 and-533 bp) in NCR1.However,two protected regions can be detected in NCR2, one between-272 and-252 bp relative to the cap site, the other between-306 and-329 bp.We also observed that HMG proteins 14 and 17 could not bind to both negative regions, so it seems that HMG proteins 1 and 2 may play an important role in the regulation of β-globin expression through DNA-protein interaction or through protein-protein interaction.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
文摘The DNasel hypersensitive site 2 (HS2) of human β-globin locus control region (LCR) is required fOr the high level expression of human d-globin genes. In the present study, a stage-specific protein factor (LPF-β) was identified in the nuclear extract prepared from mouse fetal liver at d 18 of gestation, which could bind to the HS2 region of humanβ-globin LCRt We also found that the shift band of LPF-βfactor could be competed by humanβ-globin promoter. However, it couldn’t be competed by human E-globin promoter or by human Aβ-globin promoter. Furthermore, our data demonstrated that the binding-sequence of LPF-d factor is 5’CACACCCTA 3’,which is located at the HS2 region ofβ-LCR (from -10845 to -10853 bp) and humanβ-globin promoter (from -92 to -84 bp). We speculated that these regions containing the CACCC box in both the humallβ-globin promoter and HS2 might function as stage selector elements in the regulation of humanβd-globin switching and the LPF-βfactor might be a stage-specific protein factor involved in the regulation of humanβ-globin gene expression.
文摘In order to elucidate the molecular mechanisms of globin gene expression during embryonic development, the nuclear extracts from mouse hematopoietic tissue at different stages of development have been prepared. By using DNase I footprinting and gel mobility shift assays, the binding of protein factors in these extracts to the human βglobin promoter was analyzed. The differences in the binding patterns of protein factors during development were observed. An erythroid-specific and stage-specific nuclear protein in the nuclear extract from d 18 mouse fetal liver was identified, which can bind to the sequence (from -66bp to -90bp) of human β-globin promoter. We therefore speculate that the function of this cis-acting element may be similar to stage selector element (SSE) in chieken βA- promoter.
基金Fund Project:National Natural Science Foundation of China(No.31660318)High-level Talents Project of Hainan Natural Science Foundation(No.820RC638)Innovation Project for Graduate Students in Hainan Province(No.Hys2020-377)。
文摘Objective:Studies have shown thatβ-globin gene presents a selective expression transformation mechanism during development,and its upstream locus control region(LCR)regulates the expression pattern ofβ-globin gene family.To further explore the molecular network ofβ-globin gene expression regulation,other long-range regulatory elements that may be involved in the regulation ofβ-globin gene expression were screened and the dynamic regulation and transformation mechanism ofβ-globin gene was deeply studied.Methods:Promyelocytic cells were induced to differentiate by all-trans retinoic acid.β-globin gene promoter region and LCR were used as the target sites for circular chromosome conformational capture(4C)analysis.Through sequencing and regulatory element analysis,the sites interacting withβ-globin family loci were screened in the whole genome.Results:According to the results of 4C sequencing,the sites that interact with HBD promoter region and LCR were screened.Verified by chromosome conformational capture(3C),the results were consistent with those of sequencing.The functional analysis of regulatory elements by formaldehyde-assisted separation regulatory elements and Epiregio online website showed that the screening sites AC105129.4,AL354707.17,AC078785.22 and AC021646.35 were all potential regulatory elements involved inβ-globin gene.Conclusion:The interaction between 4C screening site and anchor site showed the complex spatial organization ofβ-globin family loci in the nucleus.
基金Research and Event Incentive Fund of Hospital de Clinicas de Porto Alegre (FIPEHCPA)
文摘Hematopoietic stem cell transplantation(HSCT)has emerged as a curative strategy for sickle cell anemia(SCA);it is necessary to find markers of SCA clinical severity to spare those SCA patients whose clinical course is mild from the morbidity and mortality associated with HSCT. Haplotypes have been correlated with the severity of clinical manifestations in SCA patients, and fetal hemoglobin(HbF)and socioeconomic status(SeS)have also been described as negative factors. We studied these factors and their impact on clinical manifestations in a population of Southern Brazilian patients attending the Center for Sickle Cell Anemia at Hospital de Clínicas de Porto Alegre/RS, Brazil. Clinical severity was defined as two or more veno-occlusive episodes per year. The βS haplotypes were determined by PCR in 75 SCA patients. Among the 150 βS chromosomes analyzed, 99(66%)were identified as Bantu(Ban), 41(27%)asBenin(Ben), and 10(7%)as other haplotypes. Most patients in our sample(62.7%)belonged to lower SeS groups, precluding meaningful statistical analysis of SeS impact on clinical severity. There was no correlation between haplotypes or HbF level and SCA clinical severity. Gene polymorphisms and environmental issues have to be taken into consideration.
文摘One of the crucial tasks of fundamental studies on modern biology is to explore the regulatory mechanisms of gene expression. Yet so far little has been known about the fine structural changes induced by the interaction between the DNA and the proteins. The major obstacles arise from the fact that it is not easy to crystallize the protein-DNA complex that is generally small in amount. This prevents researchers from gaining knowledge of the local structure with X-ray crystallography. On the other hand, the resolution of the electron microscope is not high enough to reveal structural details in nanometer scale.
文摘Human β-globin gene family provides an ideal model for studying the expression and regulation of eukaryotic gene. The five transcriptional active genes arranged 5′ε-~Gγ-~Aγ-δ-β 3′ in the order that they are expressed during development. However, the molecular regulatory mechanism of the human globin gene expression remains to be defined. β-globin gene normally expressed in the adult bone marrow, but not in the embryonic stage, which
基金This work was supported by grants from Academia Sinica.
文摘The pattern of high mobility group proteins 1 and 2 (HMG1,2) interaction with the 5’-flanking sequence of the human β-globin gene has been analyzed by scanning tunnelling microscopy (STM). A 200 bp negative regulatory region in the 5’-flanking sequence of the human β-globin gene can be folded by HMG proteins 1 and 2 into a circular structure (diameter 70±6) with a linear tail which seems to be a left-handed double helix structure.
基金Project supported by grants from Academia Sinica.
文摘Our previous studies have identified that there are at least three regulatory regions (two negative regions and one positive region) in the 5'-flanking sequence of human β-globin gene (-610 to +1 bp). The binding of HMG proteins to both negative regulatory regions was examined by the gel mobility shift and DNase I protection assays.In gel mobility shift assay,we observed that HMG proteins 1 and 2 could bind to both negative regulatory regions (NCR1 and NCR2).Using the gel shift competition assay,we identified that the binding proteins between the two regions are different from each other.DNase I protection analysis shows that HMG proteins 1 and 2 only bind to one site (between-560 and-533 bp) in NCR1.However,two protected regions can be detected in NCR2, one between-272 and-252 bp relative to the cap site, the other between-306 and-329 bp.We also observed that HMG proteins 14 and 17 could not bind to both negative regions, so it seems that HMG proteins 1 and 2 may play an important role in the regulation of β-globin expression through DNA-protein interaction or through protein-protein interaction.
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.
