RRC ID 74606
Author Ohsaka Y, Ohgiya S, Hoshino T, Ishizaki K.
Title Mitochondrial genome-encoded ATPase subunit 6+8 mRNA increases in human hepatoblastoma cells in response to nonfatal cold stress.
Journal Cryobiology
Abstract Cellular responses to cold stress have not been well clarified, compared with heat shock responses, especially in mammalian cells. We investigated cold-stress responses in human hepatoblastoma cells (HepG2) exposed to a nonfatal temperature of 17 degrees C. Under the condition, RNA and protein syntheses in the cells were highly, but incompletely, depressed and cell growth was impaired. A cDNA subtraction method was used to isolate mRNAs for which the levels were increased in cold-stressed cells compared with cells cultured at 37 degrees C. A transcript isolated by the screening was identified as ATPase subunit 6+8 mRNA that encodes components of a mitochondrial ATPase complex and that is transcribed from a mitochondrial genome. The copy number of the mitochondrial genome in cells was not changed by cold stress. Thus, HepG2 cells were treated with various concentrations of actinomycin D and chloramphenicol to assess the effects of transcriptional and translational reduction on the increased level of the ATPase subunit 6+8 mRNA. The mRNA level was increased in cells treated with low concentrations of the RNA or protein synthesis inhibitors. These results indicate that the increase in ATPase subunit 6+8 mRNA stimulated by cold stress could be mediated by a partial decline of transcription and/or translation in the cells. In addition, the degradation of ATPase subunit 6+8 mRNA was suppressed in cold-stressed cells compared with that in 37 degrees C-cultured cells. This result implies that posttranscriptional regulation is also involved in the cold-stimulated increase in ATPase subunit 6+8 mRNA in HepG2 cells.
Volume 40(2)
Pages 92-101
Published 2000-3-1
DOI 10.1006/cryo.2000.2237
PII S0011-2240(00)92237-5
PMID 10788308
MeSH Apoptosis Cold Temperature* DNA Replication DNA, Complementary / genetics DNA, Mitochondrial / genetics Enzyme Induction Gene Expression Regulation, Neoplastic* Hepatoblastoma / enzymology Hepatoblastoma / pathology* Humans Liver Neoplasms / enzymology Liver Neoplasms / pathology* Proton-Translocating ATPases / genetics* RNA, Messenger / biosynthesis* RNA, Neoplasm / biosynthesis* Stress, Physiological / genetics Stress, Physiological / metabolism Subtraction Technique Tumor Cells, Cultured / enzymology
IF 2.287
Resource
Human and Animal Cells Hep G2(RCB0459)