Changes in ribosome-polyribosome balances in chick muscle cells during tissue dissociation, development in culture, and exposure to simplified culture-medium
✍ Scribed by Howard L. Hosick; Richard C. Strohman
- Book ID
- 102879965
- Publisher
- John Wiley and Sons
- Year
- 1971
- Tongue
- English
- Weight
- 851 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Abstract
The populations of polyribosomes, monomeric ribosomes, and ribosomal subunits are described from the time of tissue explantation to the time of complete muscle differentiation in primary cultures of chick muscle cells. There is extensive degradation of polyribosomes, and a net loss of ribosomes recovered, as cells of embryonic muscle are dissociated with proteolytic enzymes. The cells rapidly restore a high polysome: monomeric ribosome ratio. This recovery of the polyribosome population occurs before there is any detectable net increase in ribosome number. Ribosome production begins after a lag of approximately 15 hours in culture. Number of ribosomes/cell triples by 60 hours, at which time cell fusion (myotube formation) is complete. Unlike developing muscle in vivo, cultured cells have a very reduced pool of monomeric ribosomes. Medium simplification experiments done with fully differentiated cultures show, however, that monomers accumulate during starvation. These monomers reassociate to form polyribosomes during medium replenishment. Subunit complements are maintained at a constant level regardless of nutritional conditions. These features of cultured muscle are discussed as possible tools for further study of muscle development.