Up-regulation of telomerase in primary cultured rat hepatocytes.
Telomerase is a unique reverse transcriptase involved in the maintenance of telomeric DNA, which is generally undetectable in normal human somatic cells. However, it has been found in organs of normal adult rodents including the liver. In order to elucidate relevant control mechanisms operating in normal somatic cells, we examined telomerase activity in primary cultured rat hepatocytes. During culture under serum-free conditions, rat hepatocytes rapidly lose the ability of organ-specific expression of serum albumin, apolipoprotein A-I, and hepatocyte nuclear factor 4, and the capacity for cytochrome P-450 induction by xenobiotics. The telomerase activity was found to be concomitantly increased about 2. 5-fold at 48 h and 3-fold at 72 h. Northern blot and RT-PCR analyses with primary cultured hepatocytes revealed the associated accumulation of rat telomerase RNA subunits (TR), and the mRNAs for a telomerase reverse transcriptase (TERT) and a telomerase-associated protein (TEP1). The activity of hepatocyte telomerase, which was elevated during the primary culture, increased further when the cells were stimulated with hepatocyte growth factor. In this case, however, the levels of TR, TERT, and TEP1 mRNA did not show any detectable changes.
Nozawa
K
K
Laboratory of Cancer Cell Biology, Research Institute for Disease Mechanism and Control, Showa-ku, Nagoya, 466-8550, Japan.
Kurumiya
Y
Y
Yamamoto
A
A
Isobe
Y
Y
Suzuki
M
M
Yoshida
S
S
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002793:Cholic Acids / Q000494:pharmacology; D004268:DNA-Binding Proteins; D003902:Detergents / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D017228:Hepatocyte Growth Factor / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D008297:Male; D028044:Phosphate-Binding Proteins; D012313:RNA; D012337:RNA, Ribosomal, 18S / Q000378:metabolism; D012339:RNA, Ribosomal, 28S / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation
D002352:Carrier Proteins; D002793:Cholic Acids; D004268:DNA-Binding Proteins; D003902:Detergents; D028044:Phosphate-Binding Proteins; D012337:RNA, Ribosomal, 18S; D012339:RNA, Ribosomal, 28S; D011994:Recombinant Proteins; C498416:Tep1 protein, rat; C422952:telomerase RNA; D004815:Epidermal Growth Factor; D012313:RNA; D017228:Hepatocyte Growth Factor; C509186:TERT protein, human; D019098:Telomerase; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate