The Experts below are selected from a list of 165 Experts worldwide ranked by ideXlab platform
Harvey B Pollard - One of the best experts on this subject based on the ideXlab platform.
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novel isoforms of synexin in Xenopus laevis multiple tandem pgqm repeats distinguish mrnas in specific adult tissues and embryonic stages
Biochemical Journal, 1996Co-Authors: Meera Srivastava, Zhenyong Zhangkeck, Hung Caohuy, Peter Mcphie, Harvey B PollardAbstract:Synexin (annexin VII) is a calcium-dependent, phospholipidbinding and membrane fusion Protein in the annexin gene family, which forms calcium channels and may play a role in exocytotic secretion. We report here the cloning and characterization of five novel isoforms of cDNAs encoding Xenopus synexin from brain, oocyte and stage 24 cDNA libraries. The most prevalent Xenopus synexin has 1976 bp of cDNA sequence, which contains a 1539 bp open reading frame of 512 amino acids encoding a 54 kDa Protein. This Xenopus Protein is 6 kDa larger than the previously reported human and mouse synexins with which it shares approx. 73% identity in the C-terminal region and approx. 44% identity in the N-terminal region. Further studies with PCR revealed the molecular basis of the substantial divergence in the Xenopus synexin’s N-terminal domain. The domain equivalent to the mammalian tissue-specific cassette exon occurs at a dierent position and is variable in size and
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Novel isoforms of synexin in Xenopus laevis: multiple tandem PGQM repeats distinguish mRNAs in specific adult tissues and embryonic stages.
The Biochemical journal, 1996Co-Authors: Meera Srivastava, Hung Caohuy, Z Y Zhang-keck, Peter Mcphie, Harvey B PollardAbstract:Synexin (annexin VII) is a calcium-dependent, phospholipid-binding and membrane fusion Protein in the annexin gene family, which forms calcium channels and may play a role in exocytotic secretion. We report here the cloning and characterization of five novel isoforms of cDNAs encoding Xenopus synexin from brain, oocyte and stage 24 cDNA libraries. The most prevalent Xenopus synexin has 1976 bp of cDNA sequence, which contains a 1539 bp open reading frame of 512 amino acids encoding a 54 kDa Protein. This Xenopus Protein is 6 kDa larger than the previously reported human and mouse synexins with which it shares approx. 73% identity in the C-terminal region and approx. 44% identity in the N-terminal region. Further studies with PCR revealed the molecular basis of the substantial divergence in the Xenopus synexin's N-terminal domain. The domain equivalent to the mammalian tissue-specific cassette exon occurs at a different position and is variable in size and sequence. The most interesting observation relates to the occurrence of different forms of synexin due to the varying numbers of tandem PGQM repeats that are expressed differently in different adult tissues and embryonic stages. For these reasons we have labelled this set of unique isoforms annexin VIIb, referring to mammalian forms, which lack the PGQM tandem repeats, as annexin VIIa. In spite of these differences from annexin VIIa, the form of recombinant annexin VIIb with three PGQM repeats was found to be catalytically active. We interpret these results to indicate that the actual calcium and phospholipid binding sites are conserved in Xenopus, and that the variations observed between members of the synexin gene family in the regulatory domain clearly point towards the tissue- and stage-specific roles of individual members, possibly involving the exocytotic process.
Meera Srivastava - One of the best experts on this subject based on the ideXlab platform.
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novel isoforms of synexin in Xenopus laevis multiple tandem pgqm repeats distinguish mrnas in specific adult tissues and embryonic stages
Biochemical Journal, 1996Co-Authors: Meera Srivastava, Zhenyong Zhangkeck, Hung Caohuy, Peter Mcphie, Harvey B PollardAbstract:Synexin (annexin VII) is a calcium-dependent, phospholipidbinding and membrane fusion Protein in the annexin gene family, which forms calcium channels and may play a role in exocytotic secretion. We report here the cloning and characterization of five novel isoforms of cDNAs encoding Xenopus synexin from brain, oocyte and stage 24 cDNA libraries. The most prevalent Xenopus synexin has 1976 bp of cDNA sequence, which contains a 1539 bp open reading frame of 512 amino acids encoding a 54 kDa Protein. This Xenopus Protein is 6 kDa larger than the previously reported human and mouse synexins with which it shares approx. 73% identity in the C-terminal region and approx. 44% identity in the N-terminal region. Further studies with PCR revealed the molecular basis of the substantial divergence in the Xenopus synexin’s N-terminal domain. The domain equivalent to the mammalian tissue-specific cassette exon occurs at a dierent position and is variable in size and
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Novel isoforms of synexin in Xenopus laevis: multiple tandem PGQM repeats distinguish mRNAs in specific adult tissues and embryonic stages.
The Biochemical journal, 1996Co-Authors: Meera Srivastava, Hung Caohuy, Z Y Zhang-keck, Peter Mcphie, Harvey B PollardAbstract:Synexin (annexin VII) is a calcium-dependent, phospholipid-binding and membrane fusion Protein in the annexin gene family, which forms calcium channels and may play a role in exocytotic secretion. We report here the cloning and characterization of five novel isoforms of cDNAs encoding Xenopus synexin from brain, oocyte and stage 24 cDNA libraries. The most prevalent Xenopus synexin has 1976 bp of cDNA sequence, which contains a 1539 bp open reading frame of 512 amino acids encoding a 54 kDa Protein. This Xenopus Protein is 6 kDa larger than the previously reported human and mouse synexins with which it shares approx. 73% identity in the C-terminal region and approx. 44% identity in the N-terminal region. Further studies with PCR revealed the molecular basis of the substantial divergence in the Xenopus synexin's N-terminal domain. The domain equivalent to the mammalian tissue-specific cassette exon occurs at a different position and is variable in size and sequence. The most interesting observation relates to the occurrence of different forms of synexin due to the varying numbers of tandem PGQM repeats that are expressed differently in different adult tissues and embryonic stages. For these reasons we have labelled this set of unique isoforms annexin VIIb, referring to mammalian forms, which lack the PGQM tandem repeats, as annexin VIIa. In spite of these differences from annexin VIIa, the form of recombinant annexin VIIb with three PGQM repeats was found to be catalytically active. We interpret these results to indicate that the actual calcium and phospholipid binding sites are conserved in Xenopus, and that the variations observed between members of the synexin gene family in the regulatory domain clearly point towards the tissue- and stage-specific roles of individual members, possibly involving the exocytotic process.
Peter Mcphie - One of the best experts on this subject based on the ideXlab platform.
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novel isoforms of synexin in Xenopus laevis multiple tandem pgqm repeats distinguish mrnas in specific adult tissues and embryonic stages
Biochemical Journal, 1996Co-Authors: Meera Srivastava, Zhenyong Zhangkeck, Hung Caohuy, Peter Mcphie, Harvey B PollardAbstract:Synexin (annexin VII) is a calcium-dependent, phospholipidbinding and membrane fusion Protein in the annexin gene family, which forms calcium channels and may play a role in exocytotic secretion. We report here the cloning and characterization of five novel isoforms of cDNAs encoding Xenopus synexin from brain, oocyte and stage 24 cDNA libraries. The most prevalent Xenopus synexin has 1976 bp of cDNA sequence, which contains a 1539 bp open reading frame of 512 amino acids encoding a 54 kDa Protein. This Xenopus Protein is 6 kDa larger than the previously reported human and mouse synexins with which it shares approx. 73% identity in the C-terminal region and approx. 44% identity in the N-terminal region. Further studies with PCR revealed the molecular basis of the substantial divergence in the Xenopus synexin’s N-terminal domain. The domain equivalent to the mammalian tissue-specific cassette exon occurs at a dierent position and is variable in size and
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Novel isoforms of synexin in Xenopus laevis: multiple tandem PGQM repeats distinguish mRNAs in specific adult tissues and embryonic stages.
The Biochemical journal, 1996Co-Authors: Meera Srivastava, Hung Caohuy, Z Y Zhang-keck, Peter Mcphie, Harvey B PollardAbstract:Synexin (annexin VII) is a calcium-dependent, phospholipid-binding and membrane fusion Protein in the annexin gene family, which forms calcium channels and may play a role in exocytotic secretion. We report here the cloning and characterization of five novel isoforms of cDNAs encoding Xenopus synexin from brain, oocyte and stage 24 cDNA libraries. The most prevalent Xenopus synexin has 1976 bp of cDNA sequence, which contains a 1539 bp open reading frame of 512 amino acids encoding a 54 kDa Protein. This Xenopus Protein is 6 kDa larger than the previously reported human and mouse synexins with which it shares approx. 73% identity in the C-terminal region and approx. 44% identity in the N-terminal region. Further studies with PCR revealed the molecular basis of the substantial divergence in the Xenopus synexin's N-terminal domain. The domain equivalent to the mammalian tissue-specific cassette exon occurs at a different position and is variable in size and sequence. The most interesting observation relates to the occurrence of different forms of synexin due to the varying numbers of tandem PGQM repeats that are expressed differently in different adult tissues and embryonic stages. For these reasons we have labelled this set of unique isoforms annexin VIIb, referring to mammalian forms, which lack the PGQM tandem repeats, as annexin VIIa. In spite of these differences from annexin VIIa, the form of recombinant annexin VIIb with three PGQM repeats was found to be catalytically active. We interpret these results to indicate that the actual calcium and phospholipid binding sites are conserved in Xenopus, and that the variations observed between members of the synexin gene family in the regulatory domain clearly point towards the tissue- and stage-specific roles of individual members, possibly involving the exocytotic process.
Hung Caohuy - One of the best experts on this subject based on the ideXlab platform.
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novel isoforms of synexin in Xenopus laevis multiple tandem pgqm repeats distinguish mrnas in specific adult tissues and embryonic stages
Biochemical Journal, 1996Co-Authors: Meera Srivastava, Zhenyong Zhangkeck, Hung Caohuy, Peter Mcphie, Harvey B PollardAbstract:Synexin (annexin VII) is a calcium-dependent, phospholipidbinding and membrane fusion Protein in the annexin gene family, which forms calcium channels and may play a role in exocytotic secretion. We report here the cloning and characterization of five novel isoforms of cDNAs encoding Xenopus synexin from brain, oocyte and stage 24 cDNA libraries. The most prevalent Xenopus synexin has 1976 bp of cDNA sequence, which contains a 1539 bp open reading frame of 512 amino acids encoding a 54 kDa Protein. This Xenopus Protein is 6 kDa larger than the previously reported human and mouse synexins with which it shares approx. 73% identity in the C-terminal region and approx. 44% identity in the N-terminal region. Further studies with PCR revealed the molecular basis of the substantial divergence in the Xenopus synexin’s N-terminal domain. The domain equivalent to the mammalian tissue-specific cassette exon occurs at a dierent position and is variable in size and
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Novel isoforms of synexin in Xenopus laevis: multiple tandem PGQM repeats distinguish mRNAs in specific adult tissues and embryonic stages.
The Biochemical journal, 1996Co-Authors: Meera Srivastava, Hung Caohuy, Z Y Zhang-keck, Peter Mcphie, Harvey B PollardAbstract:Synexin (annexin VII) is a calcium-dependent, phospholipid-binding and membrane fusion Protein in the annexin gene family, which forms calcium channels and may play a role in exocytotic secretion. We report here the cloning and characterization of five novel isoforms of cDNAs encoding Xenopus synexin from brain, oocyte and stage 24 cDNA libraries. The most prevalent Xenopus synexin has 1976 bp of cDNA sequence, which contains a 1539 bp open reading frame of 512 amino acids encoding a 54 kDa Protein. This Xenopus Protein is 6 kDa larger than the previously reported human and mouse synexins with which it shares approx. 73% identity in the C-terminal region and approx. 44% identity in the N-terminal region. Further studies with PCR revealed the molecular basis of the substantial divergence in the Xenopus synexin's N-terminal domain. The domain equivalent to the mammalian tissue-specific cassette exon occurs at a different position and is variable in size and sequence. The most interesting observation relates to the occurrence of different forms of synexin due to the varying numbers of tandem PGQM repeats that are expressed differently in different adult tissues and embryonic stages. For these reasons we have labelled this set of unique isoforms annexin VIIb, referring to mammalian forms, which lack the PGQM tandem repeats, as annexin VIIa. In spite of these differences from annexin VIIa, the form of recombinant annexin VIIb with three PGQM repeats was found to be catalytically active. We interpret these results to indicate that the actual calcium and phospholipid binding sites are conserved in Xenopus, and that the variations observed between members of the synexin gene family in the regulatory domain clearly point towards the tissue- and stage-specific roles of individual members, possibly involving the exocytotic process.
Aaron Klug - One of the best experts on this subject based on the ideXlab platform.
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The Discovery of Zinc Fingers and Their Applications in Gene Regulation and Genome Manipulation
Annual review of biochemistry, 2010Co-Authors: Aaron KlugAbstract:An account is given of the discovery of the classical Cys2His2 zinc finger, arising from the interpretation of biochemical studies on the interaction of the Xenopus Protein transcription factor IIIA with 5S RNA, and of structural studies on its structure and its interaction with DNA. The finger is a self-contained domain stabilized by a zinc ion ligated to a pair of cysteines and a pair of histidines, and by an inner hydrophobic core. This discovery showed not only a new Protein fold but also a novel principle of DNA recognition. Whereas other DNA binding Proteins generally make use of the two-fold symmetry of the double helix, zinc fingers can be linked linearly in tandem to recognize nucleic acid sequences of varying lengths. This modular design offers a large number of combinatorial possibilities for the specific recognition of DNA (or RNA). It is therefore not surprising that the zinc finger is found widespread in nature, including 3% of the genes of the human genome. The zinc finger design is ideally...
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The discovery of zinc fingers and their development for practical applications in gene regulation and genome manipulation.
Quarterly reviews of biophysics, 2010Co-Authors: Aaron KlugAbstract:A long-standing goal of molecular biologists has been to construct DNA-binding Proteins for the control of gene expression. The classical Cys2His2 (C2H2) zinc finger design is ideally suited for such purposes. Discriminating between closely related DNA sequences both in vitro and in vivo, this naturally occurring design was adopted for engineering zinc finger Proteins (ZFPs) to target genes specifically. Zinc fingers were discovered in 1985, arising from the interpretation of our biochemical studies on the interaction of the Xenopus Protein transcription factor IIIA (TFIIIA) with 5S RNA. Subsequent structural studies revealed its three-dimensional structure and its interaction with DNA. Each finger constitutes a self-contained domain stabilized by a zinc (Zn) ion ligated to a pair of cysteines and a pair of histidines and also by an inner structural hydrophobic core. This discovery showed not only a new Protein fold but also a novel principle of DNA recognition. Whereas other DNA-binding Proteins generally make use of the 2-fold symmetry of the double helix, functioning as homo- or heterodimers, zinc fingers can be linked linearly in tandem to recognize nucleic acid sequences of varying lengths. This modular design offers a large number of combinatorial possibilities for the specific recognition of DNA (or RNA). It is therefore not surprising that the zinc finger is found widespread in nature, including 3% of the genes of the human genome. The zinc finger design can be used to construct DNA-binding Proteins for specific intervention in gene expression. By fusing selected zinc finger peptides to repression or activation domains, genes can be selectively switched off or on by targeting the peptide to the desired gene target. It was also suggested that by combining an appropriate zinc finger peptide with other effector or functional domains, e.g. from nucleases or integrases to form chimaeric Proteins, genomes could be modified or manipulated. The first example of the power of the method was published in 1994 when a three-finger Protein was constructed to block the expression of a human oncogene transformed into a mouse cell line. The same paper also described how a reporter gene was activated by targeting an inserted 9-base pair (bp) sequence, which acts as the promoter. Thus, by fusing zinc finger peptides to repression or activation domains, genes can be selectively switched off or on. It was also suggested that, by combining zinc fingers with other effector or functional domains, e.g. from nucleases or integrases, to form chimaeric Proteins, genomes could be manipulated or modified. Several applications of such engineered ZFPs are described here, including some of therapeutic importance, and also their adaptation for breeding improved crop plants.
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The discovery of zinc fingers and their development for practical applications in gene regulation
Proceedings of the Japan Academy Series B, 2005Co-Authors: Aaron KlugAbstract:An account is given of the discovery in 1985 of the classical Cys 2 His 2 (C 2 H 2 ) zinc finger, aris- ing from the interpretation of biochemical studies on the interaction of the Xenopus Protein transcription factor IIIA with 5S RNA, and of subsequent structural studies on its 3D structure and its interaction with DNA. Each finger constitutes a self-contained domain stabilized by a zinc ion ligated to a pair of cysteines and a pair of histidines, and by an inner structural hydrophobic core. This work showed not only a new pro- tein fold but also a novel principle of DNA recognition. Whereas other DNA binding Proteins generally make use of the two-fold symmetry of the double helix, functioning as homo- or heterodimers, zinc fingers can be linked linearly in tandem to recognize nucleic acid sequences of different lengths. This modular design offers a large number of combinatorial possibilities for the specific recognition of DNA (or RNA). It is therefore not surprising that this zinc finger is found widespread in nature, in 3% of the genes of the human genome. It had long been the goal of molecular biologists to design DNA binding Proteins for control of gene expres- sion and we have adopted the zinc finger design and principle for this purpose. We demonstrated that the zinc finger design is ideally suited for such purposes, discriminating between closely related DNA sequences both in vitro and in vivo, and we have therefore adapted this natural design for engineering zinc finger Proteins for targeting specific genes. The first example of the potential of the method was published in 1994 when a three-finger Protein was constructed to block the expression of an oncogene transformed into a mouse cell line. In the same paper we also showed that we could activate a reporter gene by target- ing a nine base pair promoter which we had inserted. Thus by fusing zinc finger peptides to repression or activation domains, genes can be selectively switched off or on. By combining the targeting zinc fingers with other effector or functional domains e.g. from nucleases or integrases, to form chimeric Proteins, genomes can be manipulated or modified. Several applications of such engineered zinc finger Proteins are described here, including some of potential therapeutic importance.
