Expression of two isoform mRNAs of nucleolar protein B23 during rat liver regeneration.
Nucleolar protein B23 exists in two isoforms designated as B23.1 and B23.2, differing only in their carboxy-terminal short sequences. To clarify the levels of protein B23 isoform mRNAs in the cell cycle, we have investigated the expressions of the two mRNAs during rat liver regeneration. Both of B23 isoforms transcripts increased after a partial hepatectomy. Peaks of the mRNAs were observed after 9 h (fivefold) with B23.1 and 12 h (twofold) with B23.2, respectively. These two peaks were slightly preceding the onset of DNA synthesis, which was revealed by the activity of DNA polymerase alpha. From these observations, important roles of both protein B23 isoforms in stimulation of DNA polymerase a activity during rat liver regeneration were suggested.
Department of Sustainable Resource Science, Faculty of Bioresources, Mie University, 1515 Kamihama, Tsu, Mie 514-8507, Japan.
Yuki
Y
Nishimura
Masahiro
M
Nishio
Yukio
Y
Furuichi
Hayato
H
Umekawa
D000818:Animals; D015152:Blotting, Northern; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D007150:Immunohistochemistry; D008099:Liver / Q000378:metabolism / Q000601:surgery; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D000090243:Nucleophosmin; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D009687:Nuclear Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D000090243:Nucleophosmin; D004259:DNA-Directed DNA Polymerase