Differences in expression of a variant actin between low and high metastatic B16 melanoma.
The polypeptides of mouse B16 melanoma lines of defined metastatic potential have been analyzed by two-dimensional electrophoresis. Parent B16 melanoma and two independently isolated B16-F1 lines, which are low metastatic, exhibited a new polypeptide, Ax (pI 5.2; Mr = 43,000), comprising approximately 30% of the total actin, in addition to normal beta- and gamma-actin. The Ax is present in the Triton-insoluble fraction (cytoskeleton and nuclear matrix) as well as in the Triton-soluble fraction at a constant ratio of about 0.5 to beta- plus gamma-actin. The Ax polypeptide has been identified as a variant form of actin by immunostaining with anti-actin antibody and by a comparison of its tryptic patterns with those produced by beta- and gamma-actin polypeptides; the Ax is also identified as a component of microfilaments. On the other hand, the Ax polypeptide disappears or its expression is very low in high metastatic lines, two independently isolated B16-F10s and B16-BL6. By in vitro translation, we have identified the mRNA species that code for Ax in B16-F1, but not in B16-F10.
Taniguchi
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S
Kawano
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T
Kakunaga
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T
Baba
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T
D000199:Actins / Q000096:biosynthesis / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D014644:Genetic Variation; D008545:Melanoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008715:Methionine / Q000378:metabolism; D051379:Mice; D009362:Neoplasm Metastasis; D010446:Peptide Fragments / Q000032:analysis; D013462:Sulfur Radioisotopes; D014357:Trypsin
D000199:Actins; D010446:Peptide Fragments; D013462:Sulfur Radioisotopes; D008715:Methionine; D014357:Trypsin