The alpha1-microglobulin/bikunin gene: characterization in mouse and evolution.
The 129Sv mouse gene coding for the alpha1-microglobulin/bikunin precursor has been isolated and characterized. The 11kb long gene contains ten exons, including six 5'-exons coding for alpha1-microglobulin and four 3'-exons encoding bikunin. Exon 7 also codes for the tribasic tetrapeptide RARR which connects the alpha1-microglobulin and bikunin parts. The sixth intron, which separates the alpha1-microglobulin and bikunin encoding parts, was compared in the human, mouse and a fish (plaice) gene. The size of this intron varies considerably, 6.5, 3.3 and 0.1kb in man, mouse and plaice, respectively. In all three genes, this intron contains A/T-rich regions, and retroposon elements are found in the first two genes. This indicates that this sixth intron is an unstable region and a hotspot for recombinational events, supporting the concept that the alpha1-microglobulin and bikunin parts of this gene are assembled from two ancestral genes. Finally, the nonsynonymous nucleotide substitution rate of the gene was determined by comparing coding sequences from ten vertebrate species. The results indicate that the alpha1-microglobulin part of the gene has evolved faster than the bikunin part.
Section for Molecular Signalling, Department of Cell and Molecular Biology, Lund University, P.O. Box 94, S-221 00, Lund, Sweden.
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A
Lindqvist
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P
Rouet
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JP
Salier
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B
Akerström
D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004742:Enhancer Elements, Genetic; D019143:Evolution, Molecular; D005091:Exons; D005796:Genes / Q000235:genetics*; D006023:Glycoproteins / Q000235:genetics*; D020071:Interspersed Repetitive Sequences; D007438:Introns; D008562:Membrane Glycoproteins; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D011506:Proteins / Q000235:genetics; D011544:Pseudogenes; D017422:Sequence Analysis, DNA; D014360:Trypsin Inhibitor, Kunitz Soybean
D002352:Carrier Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D011506:Proteins; C109148:SPINT2 protein, human; D004247:DNA; D014360:Trypsin Inhibitor, Kunitz Soybean