The gene encoding alpha-galactosidase A and gene rearrangements causing Fabry disease.
Item
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Title
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The gene encoding alpha-galactosidase A and gene rearrangements causing Fabry disease.
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Identifier
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AAI9029953
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identifier
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9029953
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Creator
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Kornreich, Ruth.
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Contributor
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Advisers: David F. Bishop | Robert J. Desnick
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Date
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1990
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Molecular
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Abstract
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Human {dollar}\alpha{dollar}-galactosidase A (EC 3.2.1.22) is a lysosomal hydrolase encoded by a single gene localized to the chromosomal region Xq21.22-q22. The deficient activity of this enzyme results in Fabry disease, an X-linked recessive disorder which leads to premature death in affected males. To study the structure of {dollar}\alpha{dollar}-galactosidase A and the molecular nature of mutations causing Fabry disease, the full-length cDNA was isolated, sequenced and used to obtain the human chromosomal gene. The 1393 base pair full-length cDNA had a 60 nucleotide 5{dollar}\sp\prime{dollar} untranslated region and encoded a precursor peptide of 429 amino acids including a signal peptide of 31 residues. The {dollar}\sim{dollar}12 kilobase chromosomal gene was sequenced in its entirety. The gene had seven exons whose sequences were identical to those in the full-length cDNA. All intron-exon splice junctions conformed to the GT/AG consensus sequence. The 5{dollar}\sp\prime{dollar} flanking region of {dollar}\alpha{dollar}-galactosidase A contained SP1 and TATA and CCAAT box promoter elements. In addition, sequence motifs corresponding to the AP1, "OCTA" and "core" enhancer elements were identified. Four direct repeats of the "chorion box" enhancer were preceded by an upstream "HTF" island. A unique feature of the noncoding regions of the {dollar}\alpha{dollar}-galactosidase A gene was the presence of 12 Alu sequences. These repetitive elements accounted for about 30% of the entire gene. The sequence information was used to characterize five naturally occurring {dollar}\alpha{dollar}-galactosidase A partial gene deletions (0.4 to 4.6 kb) and one partial gene duplication (8.1 kb) which cause Fabry disease. The breakpoints of each were determined by either cloning and sequencing the mutant gene from an affected hemizygote or by DNA amplification using the polymerase chain reaction and sequencing the genomic region containing the junction. Although the {dollar}\alpha{dollar}-galactosidase A gene contains numerous Alu elements, only a 3.2 kilobase deletion was the result of recombination between two Alu repeats. The remaining five rearrangements occurred between short direct repeats of 2-6 base pairs at the deletion/duplication termini of which only one copy was retained in the novel junction. Of particular interest was the finding of the tetranucleotide CCAG and the trinucleotide CAG (or their respective complements CTGG and CTG) at the 5{dollar}\sp\prime{dollar} breakpoints in three and four of the five {dollar}\alpha{dollar}-galactosidase A gene rearrangements involving short direct repeats, respectively, suggesting a possible functional role for these sequences in the recombinational event.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
