Stabilization of hsp70 mRNA on prolonged cell exposure to hypertonicity.
Prolonged exposure of 3T3 cells to 0.5 osM hypertonic medium induced the accumulation of hsp70 mRNAs. This increase in mRNA levels required active protein synthesis. A weak and transient activation of heat shock factor 1 (HSF1) was noted, but it was temporally uncoupled to the accumulation of the hsp70 mRNAs. Nuclear run-on assay and transfection experiments showed that hsp70 gene transcription was not affected by hypertonicity. ActD chase experiments showed that during hypertonic treatment, degradation of hsp70 mRNAs was markedly reduced. This effect did not appear to be a general phenomenon since the increase in mRNA level of another gene induced by hypertonicity (ATA2 transporter) was scarcely due to RNA stabilization. These findings suggest that hypertonic treatment increases the production of hsp70 protein in 3T3 cells via a stabilization of its corresponding mRNA.
Alfieri
Roberta R
RR
Dipartimento di Medicina Sperimentale, Sezione di Patologia Molecolare e Immunologia, Universita' degli Studi di Parma, Via Volturno 39, 43100 Parma, Italy. roberta.alfieri@unipr.it
Bonelli
Mara A
MA
Petronini
Pier Giorgio
PG
Borghetti
Angelo F
AF
D016475:3T3 Cells; D026924:Amino Acid Transport System A / Q000235:genetics; D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D000076249:Heat Shock Transcription Factors; D051379:Mice; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D012462:Saline Solution, Hypertonic; D014157:Transcription Factors; D014158:Transcription, Genetic; D014162:Transfection
D026924:Amino Acid Transport System A; D004268:DNA-Binding Proteins; D018840:HSP70 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; D012333:RNA, Messenger; D012462:Saline Solution, Hypertonic; C498798:Slc38a2 protein, mouse; D014157:Transcription Factors