Molecular cloning and nucleotide sequence of rat brain argininosuccinate lyase cDNA with an extremely long 5'-untranslated sequence: evidence for the identity of the brain and liver enzymes.
Argininosuccinate lyase (EC 4.3.2.1) is an enzyme present in the brain of ureotelic animals. Using as a probe rat liver argininosuccinate lyase cDNA, already isolated and sequenced (Amaya, Y., Matsubasa, T., Takiguchi, M., Kobayashi, K., Saheki, T., Kawamoto, S. and Mori, M., J. Biochem., 103 (1988) 177-181), we screened a rat brain cDNA library constructed in the lambda gt11 expression vector and obtained a single cDNA clone. This cDNA clone contained an open reading frame encoding a polypeptide of 461 amino acid residues (predicted Mr = 51,390), a 5'-untranslated sequence of 967 bp and a 3'-untranslated sequence of 74 bp. The length of the 5'-non-coding region of the cDNA seems to be one of the longest among the cDNAs heretofore isolated. A comparison of the brain cDNA sequence (2424 bp) with the corresponding region of the liver cDNA (1574 bp) revealed differences in 5 nucleotides. The brain clone contained A----G and C----G base differences from the hepatic sequence, resulting in amino acid changes from Tyr and Arg in the liver clone, to Cys and Gly in the brain clone, respectively. The other 3 nucleotide differences are silent with respect to the amino acid sequence of the protein. Therefore, the amino acid sequence of the brain argininosuccinate lyase, as deduced from the nucleotide sequence of its cDNA clone, was identical with that of the liver protein, except for two amino acid residues. These minor changes may reflect a microheterogeneity of the argininosuccinate lyase gene. The brain and liver enzymes seem to be encoded by the same structural gene.
Kawamoto
S
S
Department of Bacteriology, Yokohama City University School of Medicine, Japan.
Kaneko
T
T
Mizuki
N
N
Ohsuga
A
A
Fukushima
J
J
Amaya
Y
Y
Mori
M
M
Okuda
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001123:Argininosuccinate Lyase / Q000032:analysis / Q000235:genetics*; D001483:Base Sequence; D001921:Brain / Q000201:enzymology*; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis*; D008099:Liver / Q000201:enzymology*; D008190:Lyases / Q000235:genetics*; D008969:Molecular Sequence Data; D051381:Rats
D004247:DNA; D008190:Lyases; D001123:Argininosuccinate Lyase