Nutritional regulation and tissue-specific expression of the serine dehydratase gene in rat.
The mechanism of dietary regulation and tissue-specific expression of the serine dehydratase gene in rat has been studied. The hepatic serine dehydratase activity and its mRNA showed a parallel increase with increasing protein content in the diet. However, when rats that had been maintained on a high protein diet were fed a protein-free diet, the mRNA level rapidly decreased to 0.5 in 3 h, whereas the enzyme activity gradually fell to a low level over a period of 5 days. With animals maintained on a high protein diet or on a protein-free diet, we examined the sites hypersensitive to DNase I in the 5'-flanking region of serine dehydratase gene in the liver chromatins. A series of DNase I-hypersensitive sites were located within 10.5 kilobase pairs upstream of the transcription start site. The DNA regions at -3050 and -3180 (region II) and -3600 to -3850 (region III) were more susceptible to the nuclease in the expressing than in the nonexpressing liver. A reverse situation obtained at -100 (region I). Kidney contained serine dehydratase mRNA at a level of 5% of liver as determined by Northern blotting. The kidney chromatin was found to be susceptible to DNase I only at region I. No conspicuous DNase I-hypersensitive sites were observed in the relevant regions of chromatins from brain and lung, in which serine dehydratase mRNA was scarcely transcribed. These results suggest that nutritional control and tissue-specific expression of the serine dehydratase gene is closely associated with the alteration of DNase I hypersensitivity at specific sites of the 5'-flanking region of the gene.
Ogawa
H
H
Department of Biochemistry, Toyama Medical and Pharmaceutical University Faculty of Medicine, Japan.
Fujioka
M
M
Su
Y
Y
Kanamoto
R
R
Pitot
H C
HC
D000818:Animals; D015152:Blotting, Northern; D004032:Diet; D004044:Dietary Proteins / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic; D012695:L-Serine Dehydratase / Q000235:genetics* / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D015183:Restriction Mapping; D014018:Tissue Distribution
D004044:Dietary Proteins; D012333:RNA, Messenger; D012695:L-Serine Dehydratase