Globin synthesis in fibroblasts fused with erythroblasts. II. Human fibroblasts.
Fusion of human (diploid) fibroblast monolayers with erythroblasts from 3-day chick embryos resulted in cultures containing on the average 14% heterokaryons and 8% fibroblast homokaryons. When these heterokaryon-containing cultures were labeled with radioactive amino acids during the first 24 h after fusion, the proportion of labeled proteins found in the globin region of analytical polyacrylamide gels showed a 40-fold increase compared with fibroblast homokaryons (0.08% vs. 4% of protein synthesized). Incorporation of radioactivity into globin decreased sharply during the second 24 h. Purified 35S-methionine-labeled globin from heterokaryon cultures gave rise to a tryptic fingerprint containing peptides characteristic of chick embryonic globins as late as 4 days after fusion. While fibroblasts in the fusion culture continue to go through the cell cycle normally, heterokaryons stop cycling almost completely soon after fusion.
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002455:Cell Division; D002459:Cell Fusion; D002467:Cell Nucleus; D002642:Chick Embryo; D004900:Erythroblasts / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D005796:Genes; D005914:Globins / Q000096:biosynthesis*; D006801:Humans; D006822:Hybrid Cells / Q000378:metabolism*; D066298:In Vitro Techniques
D000596:Amino Acids; D005914:Globins