EXPRESSION OF SARCOPLASMIC-RETICULUM CA-2+-ATPASE AND CALSEQUESTRIN GENES IN RAT-HEART DURING ONTOGENIC DEVELOPMENT AND AGING
EXPRESSION OF SARCOPLASMIC-RETICULUM CA-2+-ATPASE AND CALSEQUESTRIN GENES IN RAT-HEART DURING ONTOGENIC DEVELOPMENT AND AGING
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DOI：
10.1161/01.res.69.5.1380
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发表时间：
1991-11-01
影响因子：
20.1
通讯作者：
SCHWARTZ, K
中科院分区：
文献类型：
--
作者：
LOMPRE, AM;LAMBERT, F;SCHWARTZ, K
关于个体发育和衰老过程中肌浆网（SR）功能变化的分子机制知之甚少，除了SR Ca 2 +-ATP酶mRNA的量在这些条件下变化。本工作的目的是确定SR成熟是否需要表达特定的亚型和同步积累的mRNA编码的蛋白质位于SR。因此，我们研究了SR钙ATP酶和calsequestrin基因在大鼠从14胎龄到24个月的不同发育阶段的表达。通过核酸酶S1作图分析心脏中主要Ca 2 +-ATP酶基因的选择性剪接，我们得出结论，心脏中表达的Ca 2 +-ATP酶基因在个体发育和衰老过程中没有差异剪接。一个单一的钙螯合蛋白mRNA亚型也检测到在大鼠心脏的发育阶段。然后通过斑点印迹法测量特异性mRNA的量，并将其标准化为18 S核糖体RNA或肌球蛋白重链mRNA。相对于18 S RNA，Ca 2 +-ATP酶mRNA的量在胎儿生命结束时和产后早期大幅增加（14-15天胎儿为9.5 +/- 0.5%，而4天胎儿为99 +/- 7%）--出生后的大鼠）。在成年期观察到稳定的高水平。在老年大鼠（24个月）中，Ca 2 +-ATP酶mRNA仅占年轻成年人（1-2个月）中观察到的量的44.6%。在胎儿-新生儿期，Ca 2 +-ATP酶mRNA浓度的增加与肌球蛋白重链mRNA浓度的增加平行，但在衰老期间，这两种mRNA并不平行进化。钙螯合蛋白mRNA的浓度也在第4天达到峰值，但在胎儿、成年和衰老大鼠中同样丰富，这支持并扩展了先前的观察结果，表明在SR成熟过程中，钙螯合蛋白的合成早于ATP酶。我们的研究结果表明，成熟的SR，这是在一定程度上负责松弛率的变化，不涉及Ca 2 +-ATP酶和钙螯合酶亚型开关，而是单一亚型的浓度变化。
Little is known concerning the molecular mechanisms responsible for changes in sarcoplasmic reticulum (SR) function during ontogenic development and aging except that the amount of SR Ca2+-ATPase mRNA varies in these conditions. The aim of the present work was to determine whether SR maturation requires expression of specific isoforms and synchronous accumulation of mRNAs encoding proteins located in SR. Thus, we have studied expression of SR Ca2+-ATPase and calsequestrin genes in the rat at different developmental stages from 14 fetal days to 24 months of age. Analysis of alternative splicing of the major Ca2+-ATPase gene expressed in heart by nuclease S1 mapping led us to conclude that the Ca2+-ATPase gene expressed in heart was not differentially spliced during ontogenic development and senescence. A single calsequestrin mRNA isoform was also detected in rat heart whatever the developmental stage. The amount of specific mRNA was then measured by dot blot and normalized to 18S ribosomal RNA or to myosin heavy chain mRNA. The amount of Ca2+-ATPase mRNA relative to 18S RNA increases substantially at the end of fetal life and in the early postnatal period (9.5 +/- 0.5% in the 14-15-day fetus versus 99 +/- 7% in the 4-day-old rat). A stable high level is observed during adulthood. In aged rats (24 months), Ca2+-ATPase mRNA represents only 44.6% the amount observed in young adults (1-2 months). In the fetal-neonatal period the increase in Ca2+-ATPase mRNA concentration is parallel to the increase in myosin heavy chain mRNA concentration, but during senescence the two mRNAs do not evolve in parallel. The concentration of calsequestrin mRNA also peaks at day 4 but is equally abundant in fetal, adult, and senescent rats, which supports and extends previous observations showing that, during maturation of SR, calsequestrin is synthesized earlier than ATPase. Our results indicate that maturation of SR, which is in part responsible for changes in relaxation rate, does not involve a Ca2+-ATPase and calsequestrin isoform switch but, rather, changes in the concentration of single isoforms.