Effect of age and dietary restriction on the expression of alpha 2u-globulin.
The effect of aging on the expression of alpha 2u-globulin was studied in liver tissue from 6-30-month-old male Fischer F344 rats. The synthesis of alpha 2u-globulin by suspensions of isolated hepatocytes decreased 90% between 6 and 22 months of age. The levels of alpha 2u-globulin mRNA and the transcription of alpha 2u-globulin genes by isolated liver nuclei decreased 80-85% between 5 and 24 months of age. Because alpha 2u-globulin has been suggested to be a "senescence marker protein," the expression of alpha 2u-globulin was measured in rats fed a diet restricted in calories. This dietary restriction procedure has been shown to increase significantly the longevity of rodents. The expression of alpha 2u-globulin was compared in liver tissue from 18-month-old rats fed ad libitum and a restricted diet (40% restriction of total calories). The synthesis, mRNA levels, and transcription of alpha 2u-globulin were 1.8-3-fold higher for liver tissue from restricted rats compared to liver tissue from rats fed ad libitum. Therefore, dietary restriction alters the age-related change in the expression of alpha 2u-globulin. Our results demonstrate that the changes in alpha 2u-globulin expression that arise during aging or dietary restriction are regulated at the level of transcription.
D000375:Aging / Q000378:metabolism*; D000510:Alpha-Globulins / Q000096:biosynthesis*; D000818:Animals; D004038:Diet, Reducing; D005786:Gene Expression Regulation; D008297:Male; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011916:Rats, Inbred F344 / Q000378:metabolism; D014158:Transcription, Genetic
D000510:Alpha-Globulins; D012333:RNA, Messenger; C013803:alpha 2u globulin