Jaiswal Y K, Kanungo M S
Department of Zoology, Banaras Hindu University, Varanasi, India.
Biochem Biophys Res Commun. 1990 Apr 16;168(1):71-7. doi: 10.1016/0006-291x(90)91676-j.
The steady-state levels of mRNA and transcription of alpha-skeletal actin (alpha-SKA) and adult myosin heavy chain (MHC) genes were measured in the skeletal, cardiac and uterine muscles of young (22-25 week) and old (123-135 week) female rats. The effects of 10(-8) M 17 beta-estradiol/dexamethasone/T3 alpha on their transcription were also studied. The data show that the alpha-SKA mRNA level is lower in the old skeletal muscle and uterus, but is higher in the old myocardium. The adult MHC mRNA level is not different in the three muscles of both the ages. The transcription of alpha-SKA gene is lower in the skeletal muscle and higher in the uterus of old rats. It is unaltered in the myocardium of old rats. The transcription of adult MHC gene is lower in the old uterus. The effects of hormones on transcription of both the genes are different in the three muscles. We show that the expression of alpha-SKA gene is tissue-specific and age-related. The over-expression of alpha-SKA gene in the old myocardium is possibly due to derepression of the gene caused by hypertrophy of cardiac myocytes, and continuous hemodynamic pressure overload on the old heart.
在年轻（22 - 25周）和年老（123 - 135周）雌性大鼠的骨骼肌、心肌和子宫肌中，检测了α-骨骼肌肌动蛋白（α-SKA）和成人肌球蛋白重链（MHC）基因的mRNA稳态水平及转录情况。还研究了10(-8) M 17β-雌二醇/地塞米松/T3α对其转录的影响。数据显示，老年大鼠骨骼肌和子宫中α-SKA mRNA水平较低，但老年心肌中该水平较高。两个年龄段大鼠的三种肌肉中成人MHC mRNA水平无差异。老年大鼠骨骼肌中α-SKA基因转录较低，子宫中转录较高，老年大鼠心肌中转录无变化。老年子宫中成人MHC基因转录较低。激素对这两个基因转录的影响在三种肌肉中有所不同。我们发现α-SKA基因的表达具有组织特异性且与年龄相关。老年心肌中α-SKA基因的过表达可能是由于心肌细胞肥大导致该基因去抑制，以及老年心脏持续的血流动力学压力过载所致。
