Mendler L, Szakonyi G, Zádor E, Görbe A, Dux L, Wuytack F
Institute of Biochemistry, Albert Szent-Györgyi Medical University Szeged, Hungary.
J Muscle Res Cell Motil. 1998 Oct;19(7):777-85. doi: 10.1023/a:1005499304147.
The level of sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA) mRNAs and proteins have been assessed by RT-PCR, immunoblotting and immunocytochemistry in the rat extensor digitorum longus (EDL) muscles during regeneration from notexin-induced necrosis. As a result of the necrosis, SERCA1 and SERCA2 declined on days 1 and 3 after administration of the toxin. Thereupon the mRNA of the fast isoform SERCA1 rapidly increased between days 5 and 10 to the normal level. The mRNA level of the "housekeeping" SERCA2b isoform increased markedly during the actual necrosis at days 1 and 5, probably due to invading cells. Then the mRNA level of the neonatal SERCA1b splice variant increased first, and exceeded the level of the adult SERCA1a transcript on day 5. At later stages of regeneration the neonatal form was gradually replaced by the adult SERCA1a form, thus recapitulating similar changes known to occur during normal ontogenesis. Along with SERCA1, the levels of the slow isoform (SERCA2a) mRNA and protein increased on day 5, but the SERCA2a mRNA levels never rose above 10% of SERCA1 and after 10 days gradually declined again. In the normal and regenerated muscles, SERCA1 was expressed in 97% of the fibres which accounted for the population of fast-twitch fibres (type IIa, type IIb and probably type IIx/d). SERCA2a was present in 6% of the fibres of normal muscle (mostly in the slow-twitch type I fibres). At the end of regeneration the number of fibres expressing SERCA2a was twice as high and were found in small groups, unlike in normal EDL, but about 50% of these clustered fibres also expressed SERCA1.
在从诺维毒素诱导的坏死中再生的大鼠趾长伸肌（EDL）中，通过逆转录聚合酶链反应（RT-PCR）、免疫印迹和免疫细胞化学评估了肌浆网/内质网Ca2+ATP酶（SERCA）mRNA和蛋白质的水平。由于坏死，在注射毒素后的第1天和第3天，SERCA1和SERCA2下降。随后，快速同工型SERCA1的mRNA在第5天至第10天迅速增加至正常水平。“管家”SERCA2b同工型的mRNA水平在第1天和第5天实际坏死期间显著增加，可能是由于侵入细胞。然后，新生儿SERCA1b剪接变体的mRNA水平首先增加，并在第5天超过成人SERCA1a转录本的水平。在再生后期，新生儿形式逐渐被成人SERCA1a形式取代，从而重现了正常个体发育过程中已知发生的类似变化。与SERCA1一起，慢同工型（SERCA2a）mRNA和蛋白质的水平在第5天增加，但SERCA2a mRNA水平从未超过SERCA1的10%，并在10天后再次逐渐下降。在正常和再生肌肉中，SERCA1在97%的纤维中表达，这些纤维构成了快肌纤维群体（IIa型、IIb型以及可能的IIx/d型）。SERCA2a存在于正常肌肉6%的纤维中（主要在慢肌I型纤维中）。在再生结束时，表达SERCA2a的纤维数量是原来的两倍，并且以小群体形式存在，这与正常EDL不同，但这些聚集纤维中约50%也表达SERCA1。
