Molecular cloning and characterization of the mouse dopamine D-3 receptor gene: An additional intron and anmRNA variant.
Item
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Title
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Molecular cloning and characterization of the mouse dopamine D-3 receptor gene: An additional intron and anmRNA variant.
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Identifier
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AAI9510661
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identifier
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9510661
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Creator
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Fu, Dingyi.
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Contributor
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Adviser: Nikolaos K. Robakis
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Date
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1994
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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 | Biology, Neuroscience | Biology, Genetics
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Abstract
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The intron-exon organization for the mouse dopamine D{dollar}\sb3{dollar} receptor gene was investigated by molecular cloning and sequencing. The coding region of this gene spans at least 43 kilobases of the genome and is composed of 7 exons interspersed by 6 introns. A novel intron of approximately 1 kilobase in length was identified in both rat and mouse dopamine D{dollar}\sb3{dollar} receptor genes. This intron splits former exon 4 of the rat dopamine D{dollar}\sb3{dollar} receptor gene into two separate exons, termed exon 4 and exon 5, containing 197 and 78 nucleotides, respectively. The new intron (termed intron 4) is located between coding nucleotides 723 and 724 of the murine D{dollar}\sb3{dollar} cDNA and corresponds by position and size to intron 5 of the dopamine D{dollar}\sb2{dollar} receptor gene. Thus, the coding regions of the dopamine D{dollar}\sb2{dollar} and D{dollar}\sb3{dollar} receptor genes contain an identical number of exons (seven exons), have a very similar genomic organization and share a high degree of nucleotide homology, strongly suggesting that both genes have a common phylogenic origin and that their divergence may result from a relatively recent evolutionary event. Besides, an intron analogous to the murine intron 4 was detected in the human dopamine D{dollar}\sb3{dollar} receptor gene.;The entire coding nucleotide sequence, including all intron-exon junctions, of the mouse dopamine D{dollar}\sb3{dollar} receptor gene was determined. This receptor shares a 94.4% homology with the rat D{dollar}\sb3{dollar} receptor at the coding nucleotide level, while their homology at amino acid level is 96.9%. The intron-exon junctions of both receptor genes occur at identical positions.;Reverse transcription-polymerase chain reaction experiments revealed a short form of mouse dopamine D{dollar}\sb3{dollar} receptor mRNA (termed D{dollar}\sb{lcub}\rm 3Short{rcub}{dollar}) which predicts that the encoded protein lacks 21 amino acids from the putative third intracellular loop of the long form of the D{dollar}\sb3{dollar} receptor. Sequence analysis suggested that D{dollar}\sb{lcub}\rm 3Short{rcub}{dollar} arised from a splicing event occurred at an internal acceptor site within exon 6, resulting in the elimination of the first 63 nucleotides from this exon. No dopamine D{dollar}\sb3{dollar} receptor mRNA variants were found deriving from alternative splicing of exon 5, although its counterpart, the cassette exon 6 in the dopamine D{dollar}\sb2{dollar} receptor gene, is alternatively spliced to give rise to the D{dollar}\sb{lcub}\rm 2Short{rcub}{dollar} isoform. These data suggest a similarity in gene structure for the dopamine D{dollar}\sb2{dollar} and D{dollar}\sb3{dollar} receptors but a diversity at the post-transcriptional level during pre-mRNA splicing.
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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.
