PMID- 11171067
OWN - NLM
STAT- MEDLINE
DCOM- 20010405
LR  - 20190501
IS  - 0264-6021 (Print)
IS  - 1470-8728 (Electronic)
IS  - 0264-6021 (Linking)
VI  - 353
IP  - Pt 3
DP  - 2001 Feb 1
TI  - Cholesterol biosynthesis from lanosterol: molecular cloning, chromosomal 
      localization, functional expression and liver-specific gene regulation of rat 
      sterol delta8-isomerase, a cholesterogenic enzyme with multiple functions.
PG  - 689-99
AB  - Sterol Delta(8)-isomerase (SI) (EC 5.3.3.5), also known as emopamil binding 
      protein or sigma receptor, catalyses the conversion of the 8-ene isomer into the 
      7-ene isomer in the cholesterol biosynthetic pathway in mammals. Recently, 
      mutations of SI have been found to be associated with Conradi-Hunermann syndrome 
      in humans. To investigate the in vitro and in vivo modes of molecular regulation 
      of SI and its role in cholesterol biosynthesis in mammals, we isolated a 
      full-length cDNA encoding rat SI. The deduced amino-acid sequence of rat SI 
      predicts a 230-residue protein (26737 Da) with 87% and 80% amino-acid identity to 
      mouse and human counterparts. The rat SI gene was mapped to chromosome 12q1.2 
      using fluorescence in situ hybridization (FISH). The biological function of the 
      cloned rat SI cDNA was verified by overexpressing recombinant Myc-SI in 
      Saccharomyces cerevisiae. It showed a characteristic pattern of inhibition on 
      exposure to trans-2-[4-(1,2-diphenylbuten-1-yl)phenoxy]-N,N-dimethylethylamine 
      (tamoxifen; IC(50)=11.2 microM) and 
      3beta-[2-(diethylamino)ethoxy]androst-5-en-17-one (U18666A; IC(50)=4.2 microM), 
      two well known potent inhibitors of SI. Northern-blot analysis of 3-week-old rats 
      compared with 2-year-old rats showed that SI mRNA expression in both age groups 
      was restricted to liver, where a 70% reduction in mRNA levels was observed in 
      2-year-old rats. The FISH studies revealed ubiquitous expression of SI mRNA in 
      rat hepatocytes. The in vitro studies showed that the SI mRNA was highly 
      suppressed by 25-hydroxycholesterol in H4IIE cells. Treatment of H4IIE cells 
      grown in medium supplemented with fetal bovine serum with tamoxifen for 24 h 
      resulted in a dose-dependent induction of SI mRNA, with a concomitant suppression 
      of sterol regulatory element binding protein-1 mRNA. Interestingly, this effect 
      was not seen in emopamil-treated cells. The in vivo experiments also indicate 
      that both mRNA expression and enzymic activity of SI in liver were induced 
      approx. 3-fold in rats fed 5% (w/w) cholestyramine plus 0.1% (w/w) lovastatin in 
      normal chow for 2 weeks. With this newly cloned rat SI cDNA, it becomes possible 
      to gain molecular understanding of previously unknown and tamoxifen-mediated gene 
      regulation of SI that is involved in cholesterol metabolism, ischaemia and 
      genetic diseases.
FAU - Bae, S
AU  - Bae S
AD  - Department of Biochemistry, Yonsei Proteome Research Center and Bioproducts 
      Research Center, Yonsei University, 134 Shinchon-dong, Sudaemoon-ku, Seoul 
      120-749, Korea.
FAU - Seong, J
AU  - Seong J
FAU - Paik, Y
AU  - Paik Y
LA  - eng
SI  - GENBANK/AF071501
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - England
TA  - Biochem J
JT  - The Biochemical journal
JID - 2984726R
RN  - 0 (Anticholesteremic Agents)
RN  - 0 (DNA, Complementary)
RN  - 0 (RNA, Messenger)
RN  - 0 (Sterols)
RN  - 094ZI81Y45 (Tamoxifen)
RN  - 1J05Z83K3M (Lanosterol)
RN  - 97C5T2UQ7J (Cholesterol)
RN  - EC 5.3.3.- (Steroid Isomerases)
RN  - EC 5.3.3.- (delta(8)-delta(7)-sterol isomerase)
SB  - IM
MH  - Amino Acid Sequence
MH  - Anticholesteremic Agents/pharmacology
MH  - Base Sequence
MH  - Cholesterol/*biosynthesis
MH  - *Chromosome Mapping
MH  - Cloning, Molecular
MH  - DNA, Complementary
MH  - *Gene Expression Regulation, Enzymologic/drug effects/physiology
MH  - In Situ Hybridization, Fluorescence
MH  - Lanosterol/*metabolism
MH  - Liver/*enzymology
MH  - Molecular Sequence Data
MH  - RNA, Messenger/genetics
MH  - Sequence Homology, Amino Acid
MH  - Steroid Isomerases/*genetics/*metabolism
MH  - Sterols/metabolism
MH  - Tamoxifen/pharmacology
PMC - PMC1221616
EDAT- 2001/02/15 11:00
MHDA- 2001/04/06 10:01
PMCR- 2001/08/01
CRDT- 2001/02/15 11:00
PHST- 2001/02/15 11:00 [pubmed]
PHST- 2001/04/06 10:01 [medline]
PHST- 2001/02/15 11:00 [entrez]
PHST- 2001/08/01 00:00 [pmc-release]
AID - 10.1042/0264-6021:3530689 [doi]
PST - ppublish
SO  - Biochem J. 2001 Feb 1;353(Pt 3):689-99. doi: 10.1042/0264-6021:3530689.