Differential [32P]-labeling of chemically induced stress proteins in S-phase mouse lymphoma cells.
A portion of our research involves the investigation of biomarkers as preclinical indicators of toxic stress. Stemming from this effort, we report three unique proteins that phosphorylate and synthesize during the S-phase of lymphoma cells following chemical insult. Mouse lymphoma cell nuclei were physically sorted (using a fluorescence activated cell sorter) from partitions of the cell cycle and specific nuclear proteins in each partition were examined by gel microelectrophoresis. The changes in [32P]-incorporation by stress proteins (SPs) were examined in each of seven partitions following administration of sodium arsenite. Four SPs [80,000-84,000 relative molecular mass (Mr)], designated 'c','b','x', and 'y', underwent significant alterations in [32P]-labeling and each exhibited varying degrees of differential [32P]-incorporation in partition 3 of G1 phase, all five partitions of S-phase, and partition 1 of G2 phase of the cell cycle. Three other predominantly S-phase SPs (designated S1, S2 and S3) were phosphorylated after sodium arsenite treatment. Stress protein S1 was labeled exclusively in S-phase, while proteins S2 and S3 were labeled only in partition 3 of G1 and S-phase. Stress protein S1 possessed an identical isoelectric point, molecular mass, distribution of polypeptide fragments and immunochemical determinants as S-phase SPs found previously in mouse spleen (X') and mouse liver (LP-S). The identical biochemical characteristics of these three S-phase (SPs), found in diverse tissue types, suggest they are homologous.
Pipkin
J L
JL
Department of Health and Human Services, Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas 72079.
Anson
J F
JF
Hinson
W G
WG
Burns
E R
ER
Casciano
D A
DA
D000818:Animals; D001151:Arsenic / Q000494:pharmacology; D018053:Arsenites; D002467:Cell Nucleus / Q000737:chemistry / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology; D015180:Electrophoresis, Gel, Two-Dimensional; D006360:Heat-Shock Proteins / Q000032:analysis*; D007526:Isoelectric Point; D007545:Isoproterenol / Q000494:pharmacology; D008099:Liver / Q000737:chemistry / Q000187:drug effects; D008223:Lymphoma / Q000737:chemistry*; D051379:Mice; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000378:metabolism; D010449:Peptide Mapping; D010634:Phenobarbital / Q000494:pharmacology; D010761:Phosphorus Radioisotopes; D016196:S Phase; D017670:Sodium Compounds; D013154:Spleen / Q000737:chemistry; D014407:Tumor Cells, Cultured
D018053:Arsenites; D006360:Heat-Shock Proteins; D009687:Nuclear Proteins; D010761:Phosphorus Radioisotopes; D017670:Sodium Compounds; D003208:Concanavalin A; C017947:sodium arsenite; D007545:Isoproterenol; D001151:Arsenic; D010634:Phenobarbital