Comparison of salt-extractable nuclear proteins of regenerating liver, fetal liver, and Morris hepatomas 9618A and 3924A (original) (raw)

The nuclear proteins of regenerating and fetal rat liver, slow growing Morris hepatoma 961 8A, and fast-growing Morris hepatoma 3924A, sequentially extracted from nuclei with (a) 0.075 M NaCl/0.O25 M EDTA, (b) 10 mMTnis,(c) 0.35 M NaCl, (d) 0.6 M NaCI, and (e) 3 M NaCI/7 M urea, were analyzed by two-dimensional, isoelectric-focusing sodium dodecyl sulfate gel electrophoresis. Many of the protein spots were common to these tissues as well as to the Novikoff hepatoma and normal liver. The protein patterns of the regenerating liver and slow growing 961 8A hepatoma were more similar to that of normal liver than to those of other tissues. Many similarities were found between the fetal liver and the fast-growing 3924A and Novikoff hepatomas. Four protein spots, 64/5.9, 60/6.3, 51 /5.3, and 38/7.3 (M.W. x 1O'3/pI), were only found in the fast-growing 3924A and Novikoff hepatomas. Proteins 79/6.4 and 61/7.2 were only found in the three hepatomas. Protein 37/6.3 was dense in the three hepatornas and much less dense in the regenerating and fetal livers. Two proteins, 28/5.0 and 27/ 4.9, were detected only in the fast-growing 3924A and Novikoft hepatomas and fetal liven. Proteins 125/8.2 and 98/8.4 were found in the fetal liver and the three hepatomas; these proteins may be â€ẫ€˜oncofetal' â€p roteins. Three proteins, 61 /5.5, 56/5.8, and 53/7.5, that were absent from other tissues were present in the regenerating liver, fast-growing 3924A and Novikoff hepatomas, fetal liver, and slow-growing 961 8A hepatoma. These proteins may be related to growth processes of normal and tumor tissues studied.