title: Analysis of protein incorporation of radioactive isotopes in the Chinese hamster ovary cell cycle by electronic sorting and gel microelectrophoresis.
abstract: The patterns of [3H]-leucine and [32P]-phosphate incorporation of proteins extracted with varying molarities of sodium chloride were analyzed from nuclei physically sorted from six fluorescence windows after propidium iodine staining of the G0 + G1 and G2 + M phases of the Chinese hamster ovary (CHO) cell cycle. Eight hundred nanograms of protein were used in each electrophoretic analysis obtained from 200,000 nuclei, a portion of the sample, from each window. Autoradiography was performed in a two-dimensional polyacrylamide gel ultra-microelectrophoresis apparatus (UMEA) designed and fabricated in this laboratory. There was a net reduction and/or loss of [3H]-leucine- and [32P]-phosphate-labeled protein regions from the autoradiographs occurring primarily in the G2 + M phase. Two phosphorylated proteins that were stage specific were observed in partitions of the G2 + M phase. The use of isolated proteins and the coelectrophoresis of these markers demonstrated the similarity in mobility of a number of proteins seen in the autoradiographs of proteins extracted with high and low salt molarities and implied they are synonymous. Coelectrophoresis indicated that a substantial number of high molecular weight proteins that decreased or disappeared at late stages of G2 + M and early mitosis were composed, in part, of nucleolar proteins.
mesh_terms: D000818:Animals; D002453:Cell Cycle; D002460:Cell Line; D002469:Cell Separation; D006224:Cricetinae; D003412:Cricetulus; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D009698:Nucleoproteins / Q000032:analysis*; D010053:Ovary; D010766:Phosphorylation; D011868:Radioisotopes
chemical_list: D009698:Nucleoproteins; D011868:Radioisotopes