Induction of heat shock protein 70 and nucleolin and their intracellular distribution during early stage of liver regeneration.
Our previous work demonstrated a simultaneous induction of Hsp70 and nucleolin mRNA during the prereplicative stage of hepatocytes after partial hepatectomy [Ohmori, H. et al. (1990) Exp. Cell Res. 189, 227-232]. In the present study, changes of intracellular localization of these proteins were examined. Nucleolin, which mainly localized in the nucleus, increased with time and accumulated in the nucleolus around 12-18 h after partial hepatectomy. Hsp70 protein also increased slightly around 6-12 h after the operation. In accordance with this increase, immunohistochemical staining revealed that almost all nuclei of hepatocytes became Hsp70-positive, although Hsp70 was seen to be dispersed throughout the nucleoplasm and nucleolus at all times examined. Next, we isolated a cDNA clone of ribosomal protein (S-17) and examined its behavior. Induction of S-17 mRNA was observed to be essentially similar to that of nucleolin mRNA in regenerating rat liver, although inductions of histone H2A and H4 occurred at a later time, that is, in parallel with DNA synthesis. Furthermore, we observed a simultaneous induction of Hsp70 and nucleolin mRNA by serum-stimulation after serum-depletion in HeLa and IAR-20 (rat) culture cells. These results suggest that the induction of Hsp70, in addition to nucleolin, was not fortuitous but may be involved in the early events of liver regeneration.
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002455:Cell Division / Q000235:genetics; D002460:Cell Line; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D005786:Gene Expression Regulation; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D006498:Hepatectomy; D006657:Histones / Q000235:genetics; D007150:Immunohistochemistry; D008099:Liver / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D009687:Nuclear Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D009697:Nucleolus Organizer Region / Q000235:genetics / Q000378:metabolism*; D010750:Phosphoproteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D051381:Rats; D017207:Rats, Sprague-Dawley; D012269:Ribosomal Proteins / Q000235:genetics; D000097796:Nucleolin
D018840:HSP70 Heat-Shock Proteins; D006657:Histones; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins; D000097796:Nucleolin