The role ofc-myc in mouse myoblast differentiation.
Item
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Title
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The role ofc-myc in mouse myoblast differentiation.
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Identifier
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AAI9130337
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identifier
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9130337
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Creator
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Kohtz, Jhumku Dutt.
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Contributor
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Adviser: Edward M. Johnson
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Date
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1991
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Molecular
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Abstract
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C2 mouse myoblasts are a rapidly growing immortalized cell line capable of differentiating into multinucleated myotubes and expressing muscle-specific markers. It is known that serum-rich medium maintains their undifferentiated state; shortly after its replacement serum poor medium, cells cease proliferating, and biochemical and morphological changes associated with differentiation occur. In this thesis, it is found that upon induction of differentiation, c-myc mRNA steady state levels decrease transiently; this decrease occurs at the transcriptional level. Although the function of c-myc has yet to be delineated, it has been implicated in controlling differentiation in a variety of systems. This thesis addresses whether the decrease in c-myc expression is an obligatory event in myogenesis. One approach used is to constitutively express c-myc in C2 myoblasts, and test the effects on differentiation. Both the C2 line and a C2 subclone, C25, are used. It is found that c-myc over-expression (8-fold) in a transfected C25 clone (C5M15) can inhibit differentiation, as indicated by a failure of this cell line to accumulate myosin heavy chain, and troponin T. At lower levels (2-5 fold), however, c-myc transfection allows isolation of myoblast clones which express higher levels of differentiation markers than the parental C25 line. These results imply concentration dependent effects of the c-myc gene during myoblast differentiation. Because C25 is a myod1 negative, myogenin positive (dominantly acting, myogenic phenotype inducing genes, Davis et. al., (1988), Wright et. al., (1989)) myoblast line, questions as to how myogenesis occurs in the presence and absence of myod1 are also addressed. Using a previously established, myod1 positive, myoblast line (C2C12, Blau et. al., 1985) the differentiation properties of the two myoblast lines are compared.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
