title: Differential phosphate labeling of stress protein polypeptides in toxic dose response during S-phase of mouse lymphoma cells: a micro-electrophoretic study.
abstract: Following dosing with various levels of sodium arsenite (NaAsO2), differential [32P]-incorporation (turnover) of polypeptide fragments, generated by protease V8, from a set of four closely related stress proteins (SPs), termed 'c','b','x' and 'y', (80,000-84,000 Mr) was investigated by polyacrylamide gel (PAG) autoradiography. These SPs were physically sorted sequentially from five partitions of S-phase of a mouse lymphoma cell line (YAC-1). The fragments of each of the four SPs exhibited differential [32P]-incorporation patterns with progression in S-phase following varied dose levels of NaAsO2. The majority of V8 protease-fragments of the four SPs had identical electrophoretic mobilities. A minority of polypeptides showed varied distribution among the four SPs and these fragments revealed increased [32P]-labeling progressively in S-phase. These fragments were the most sensitive to altered dose levels of NaAsO2. It was suggested that these four SPs are discrete but structurally similar proteins. A group of other SPs (S1, S2 and S3) observed predominantly in S-phase, showed reduction in polypeptide labeling during S with varied dosing of NaAsO2. The [32P]-labeling of fragments from the SPs seems generally to follow an ordered scheme of turnover (phosphorylation-dephosphorylation) during S-phase.
authors.affiliation: Department of Health and Human Services, Food and Drug Administration, National Center for Toxicological Research, Jefferson, Arkansas 72079.
authors.forename: J L
authors.initials: JL
authors.lastname: Pipkin
authors.forename: J F
authors.initials: JF
authors.lastname: Anson
authors.forename: W G
authors.initials: WG
authors.lastname: Hinson
authors.forename: E R
authors.initials: ER
authors.lastname: Burns
authors.forename: D A
authors.initials: DA
authors.lastname: Casciano
mesh_terms: D000818:Animals; D001151:Arsenic / Q000494:pharmacology; D018053:Arsenites; D001345:Autoradiography; D015415:Biomarkers; D002467:Cell Nucleus / Q000737:chemistry / Q000187:drug effects; D004247:DNA / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D006360:Heat-Shock Proteins / Q000032:analysis* / Q000235:genetics; D006868:Hydrolysis; D008223:Lymphoma / Q000737:chemistry*; D051379:Mice; D008970:Molecular Weight; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D016196:S Phase; D017670:Sodium Compounds; D014407:Tumor Cells, Cultured
chemical_list: D018053:Arsenites; D015415:Biomarkers; D006360:Heat-Shock Proteins; D010761:Phosphorus Radioisotopes; D017670:Sodium Compounds; C017947:sodium arsenite; D004247:DNA; D001151:Arsenic