We report that gene dosage, or the ratio of nuclei from two cell types fused to form a heterokaryon, affects the time course of differentiation-specific gene expression. The rate of appearance of the human muscle antigen, 5.1H11, is significantly faster in heterokaryons with equal or near-equal numbers of mouse muscle and human fibroblast nuclei than in heterokaryons with increased numbers of nuclei from either cell type. By 4 d after fusion, a high frequency of gene expression is evident at all ratios and greater than 75% of heterokaryons express the antigen even when the nonmuscle nuclei greatly outnumber the muscle nuclei. The kinetic differences observed with different nuclear ratios suggest that the concentration of putative trans-acting factors significantly influences the rate of muscle gene expression: a threshold concentration is necessary, but an excess may be inhibitory.
Article| January 01 1986
Expression of muscle genes in heterokaryons depends on gene dosage.
G K Pavlath
H M Blau
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1986) 102 (1): 124–130.
G K Pavlath, H M Blau; Expression of muscle genes in heterokaryons depends on gene dosage.. J Cell Biol 1 January 1986; 102 (1): 124–130. doi: https://doi.org/10.1083/jcb.102.1.124
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