Characterization of a rat variant alpha-fetoprotein.
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Watanabe T, Jimenez-Molina JL, Chou JY
Characterization of a rat variant alpha-fetoprotein.
Biochem Biophys Res Commun. 1992 Jun 15;185(2):648-56.
- PubMed ID
- 1376990 [ View in PubMed]
- Abstract
The rat adult liver and hepatocyte lines express an 1.7-kb variant alpha-fetoprotein (AFP) mRNA which differs from the 2.2-kb fetal AFP transcript in sequence in the 5' region. Here we report the characterization of a variant AFP cDNA, ARFP9, which is 1349 bp in length and encodes a 325 amino acid polypeptide. Nucleotides 225 to the 3' end (1125 bp) in ARFP9 corresponds exactly to nucleotide 873 to the 3' end of the fetal AFP mRNA. However, the first 224-bp of ARFP9, which is located in the 7th intron (designated the V exon) of the rat AFP gene, is not present in the 2.2-kb fetal AFP transcript. The size of the V exon is about 266-bp. In vitro expression experiments showed that the variant AFP is an unglycosylated intracellular protein of 37 kDa. Methyl-isobutyl-xanthine (MIX) stimulated expression of the fetal AFP mRNA but inhibited expression of the variant AFP mRNA, suggesting that in the rat, the two AFP transcripts are developmentally and differentially regulated.