Apolipoprotein A-1 of Japanese quail: cDNA sequence and modulation of tissue expression by cholesterol feeding.
Apolipoprotein (apo) A-1 cDNA was amplified by the reverse-transcriptase-polymerase chain reaction (RT-PCR). Primers were synthesized according to the nucleotide sequence of chicken apo A-1, and the identity of apo A-1 cDNA was confirmed by comparing with the N-terminal amino acid sequence. The open reading frame of apo A-1 cDNA consists of 795 nucleotides, and it is capable of coding a polypeptide of 264 amino acids. A comparison between quail and chicken apo A-1 revealed 94.5% homology in the nucleotide sequence and 91.7% homology in the amino acid sequence. There was a similar 11- or 22-amino acid repeat in quail apo A-1 as was the case for chicken apo A-1. Apo A-1 mRNA was evaluated to be 1.4 k in length and was expressed in various tissues of Japanese quail: the liver, small intestine, lung, kidney, heart, and muscle. A quantitative evaluation, however, revealed that the liver and small intestine were the major organs for apo A-1 synthesis, accounting for more than 90% of the total expression of apo A-1 mRNA. Besides apo A-1 mRNA (1.4 k in length), a transcript of 4.1 k was detected in all the tissues examined, with a magnitude ranging from 5 to 10% of the apo A-1 mRNA level. The effect of cholesterol level on the expression of apo A-1 mRNA was studied to address the physiological significance of apo A-1 in the liver, small intestine, and muscle. The level of cholesterol in the liver and breast muscle was increased by feeding with cholesterol and reached a saturation level at day 7. There was also a temporal rise of cholesterol level at day 7 in the small intestine. Dietary cholesterol increased the expression of apo A-1 mRNA two fold in both the liver and small intestine. This was not the case for breast muscle, in which the expression of apo A-1 mRNA was not modulated by the cholesterol level.
Oku
H
H
Laboratory of Applied Biochemistry, Faculty of Agriculture, University of The Ryukyus, Okinawa, Japan.
Toda
T
T
Nagata
J
J
Ishikawa
M
M
Neyazaki
K
K
Shinjyo
C
C
Chinen
I
I
D000595:Amino Acid Sequence; D000818:Animals; D016632:Apolipoprotein A-I / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D002791:Cholesterol, Dietary / Q000378:metabolism / Q000494:pharmacology*; D003370:Coturnix; D018076:DNA, Complementary; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D012333:RNA, Messenger
D016632:Apolipoprotein A-I; D002791:Cholesterol, Dietary; D018076:DNA, Complementary; D012333:RNA, Messenger