1992 Fiscal Year Final Research Report Summary
Participation of cell-cell communication in muscle differentiation
| Project/Area Number |
03833020
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
分子細胞生物学
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| Research Institution | Osaka University |
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Principal Investigator |
MIMURA Naotoshi Osaka University. Institute for Protein Research. Instructor, たんぱく質研究所, 助手 (80157586)
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| Project Period (FY) |
1991 – 1992
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| Keywords | N-CAM / Muscle-Differentiation / MSD / Brefeldin A / Myogenin / Myo D |
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| Research Abstract |
To discriminate subtypes of neural cell adhesion molecules(N-CAMs) expressed during skeletal muscle differentiation, site-specific antibodies against neural cell adhesion molecule(N-CAM) were prepared with synthetic peptides covering the carboxyl-terminal half of muscle specific domain(MSD), a part of cytoplasmic domain and an extracellular region common in all N-CAMs as antigens, respectively.
Using above antibodies, all N-CAMs in muscle were classified into major three subtypes with a minor novel one with regard to inserion or deletion of two alternative-spliced domains, cytoplasmic domain and MSD(muscle specific domain). Of the three major types, the largest one with apparent molecular weight of 155kDa was recognized with all of three antibodies by immunoblotting. indicating that this type is carrying both cytoplasmic tail and MSD. Immunoblotting analysis have also shown that the smaller two with apparent molecular weight of 145kDa and 120kDa are expressed with cytoplasmic tail but w
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ithout MSD for the former type and vice versa for the latter one. Furthermore,the 120kDa form was found to be anchored to cell membrane through phosphatidyl inositol moiety instead of membrane-spanning region, since PI-PLC treatment caused the 120kDa form release from cell membrane.
During chicken embryonic development, stage-specific expression was observed in thigh muscle. The 155kDa appeared in 5th day embryo and culminated at 11th through 14th embryonic day when myoblast fusion proceed extensively to form large multinucleated myotubes, and then declined to undetectable level again at 18th embryonic day just before hatching. The 145kDa have been already detected earlier, then expressed maximally at 5th day and the after appeared to decrease gradually with progress of ermbryonic development. The 120kDa were initially expressed without MSD and gradually replaced by the form with MSD as development proceed. Finally, MSD- containing form became predominant in the 120kDa type when myotube formation were observed most extensively. From above results, MSD, the domain specifically expressed in muscle N-CAM seems to be involved in the process of myoblast fusion to form myotubes.
Nextly, brefeldin A was found to exhibit an inhibitory effect on muscle-differentiation dependent expression and accumulation of creatine kinase, myogenin and myoD in mRNA level as well as cessation of myoblast fusion. Furthermore, this inhibitory effect was not mediated by degradation of mRNA but repression of transcriptional activities. Considering that brefeldin A is a specific blocker of membrane transport to cell membrane, the action of brefeldin A suggests the possible involvement of signal transduction mediated by cell surface receptor in muscle differentiation. Less
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Research Products
(2 results)
