Zádor, Ernő and Dux, László and Wuytack, F. (1999) Prolonged passive stretch of rat soleus muscle provokes an increase in the mRNA levels of the muscle regulatory factors distributed along the entire length of the fibers. JOURNAL OF MUSCLE RESEARCH AND CELL MOTILITY, 20 (4). pp. 395-402. ISSN 0142-4319
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Abstract
The mRNA levels of the adult and the neonatal sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPases (SERCA1a and SERCA1b, respectively) and those of the muscle regulatory factors (MRFs: myoD, myf-5, myogenin, MRF4) have been assessed by RT PCR in rat soleus muscles immobilized for 3 days in an extended position (passive stretch). The transcript level of the fast type SERCA1a Ca(2+)-transport ATPase decreased to half of its normal value, whereas that of neonatal SERCA1b isoform increased 5-fold above control in stretched muscles. Immunostaining of muscle cross sections showed that the fraction of fibers expressing the SERCA1a protein was decreased evenly along the length of the stretched muscles indicating that a transformation occurred of fast fibers to slow ones. The mRNA levels of MRFs were elevated 3- to 6-fold above the normal level and were distributed evenly along the length of the stretched muscles. However in the controls these transcripts were more abundant at both ends of the muscle. The stretch increased the level of myoD and immunocytochemistry showed the expression of myoD protein in a number of nuclei of the stretched muscles whereas it was practically undetectable by this method in the control muscles. Western blotting did not indicate a significant stretch-induced increase in the level of the myogenin protein, in spite of the fact that immunocytochemistry tended to show more myogenin-positive nuclei in stretched muscles as compared to the controls. These data indicate that after 3 days of passive stretch the central and the terminal parts of the soleus muscle adapt similarly by increasing the levels of the MRFs, by decreasing the overall levels of the fast SERCA1-type of ATPase and by partially re-establishing a neonatal mode of alternative SERCA1 transcript splicing resulting in an increased SERCA1b/1a ratio.
Item Type: | Article |
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Subjects: | Q Science / természettudomány > QH Natural history / természetrajz > QH301 Biology / biológia > QH3011 Biochemistry / biokémia Q Science / természettudomány > QP Physiology / élettan |
SWORD Depositor: | MTMT SWORD |
Depositing User: | MTMT SWORD |
Date Deposited: | 06 Sep 2013 09:12 |
Last Modified: | 06 Sep 2013 09:12 |
URI: | http://real.mtak.hu/id/eprint/6484 |
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