Tumor-associated expression of a serum protein, termed aX protein (alpha 1-inhibitor III), and its mRNA in rat liver.
A cDNA clone bearing the mRNA sequence for rat alpha X protein (alpha X) was isolated from a cDNA library constructed from rat liver mRNA. The nucleotide sequence of alpha X protein cDNA showed 97% homology with that of the 3'-proximal domain of alpha 1-inhibitor III cDNA. The amino acid sequence deduced from that of alpha X cDNA also exhibited high homology with the primary sequences of alpha 1-inhibitor III and alpha 2-macroglobulin. K231 ascites hepatoma cells were transplanted into male ACI rats, and the level of alpha X mRNA in the liver of the tumor-bearing rats was determined by RNA blot hybridization with the cDNA probe. The serum concentration of alpha X decreased to about 30% of the control value with time after transplantation. The amount of alpha X mRNA in the liver of tumor-bearing rats was proportional to the serum concentration of alpha X. The serum concentrations of transferrin and albumin in the tumor-bearing rats also decreased to about 30 and 60% of the normal levels, respectively. However, the amounts of mRNAs for transferrin and albumin in the liver of tumor-bearing rats did not decrease. These findings indicate that the mechanisms of tumor-associated decrease in the concentrations of different serum proteins in tumor-bearing rats may differ.
Sugiyama
K
K
Department of Chemistry, Sasaki Institute, Tokyo.
Izumi
S
S
Tomino
S
S
Nagase
S
S
D000209:Acute-Phase Proteins; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001798:Blood Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D015152:Blotting, Northern; D005786:Gene Expression Regulation; D015723:Gene Library; D005796:Genes; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D011480:Protease Inhibitors / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D051381:Rats; D011912:Rats, Inbred ACI; D014158:Transcription, Genetic
D000209:Acute-Phase Proteins; D001798:Blood Proteins; D011480:Protease Inhibitors; D012333:RNA, Messenger; C017894:alpha 1-inhibitor 3