title: Transcription factor CAAT/enhancer-binding protein is involved in regulation of expression of sterol carrier protein x in Spodoptera litura.
abstract: The Spodoptera litura sterol carrier protein x (SlSCPx) gene is expressed in various tissues throughout the life cycle and plays important role in sterol absorption and transport. In this study, the effects of insect hormones (20-hydroexcdysone and juvenile hormone) and lipids (arachidonic acid, cholesterol) on the expression of SlSCPx was analysed by reverse-transcriptase PCR. The results showed that none of these substances significantly induced the expression of SlSCPx in Spodoptera litura-221 (Spli-221) cells. To identify the transcription factors responsible for regulation of SlSCPx expression, a 3311-bp promoter sequence of the gene was cloned. Transcriptional activity of the promoter was studied using an in vivo promoter/reporter system and a 29-bp sequence between -1000 and -1029 nucleotides (nt) upstream of this gene was found to be responsible for the up-regulation of the gene. Over-expression of CAAT/enhancer-binding protein (C/EBP) in Spli-221 cells increased the promoter activity 5.57-fold. An electrophoretic mobility shift assay showed that two nuclear proteins bound to this sequence. Recombinant C/EBP specifically bound with a putative cis-regulatory element (CRE). Mutation of the C/EBP CRE abolished the binding of the C/EBP with the CRE. These results suggest that the transcription factor C/EBP may regulate the expression of SlSCPx by binding to the CRE in the promoter of this gene.
authors.affiliation: Laboratory of Molecular and Developmental Entomology, Guangdong Provincial Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China.
authors.forename: L-N
authors.initials: LN
authors.lastname: Liang
authors.affiliation: Laboratory of Molecular and Developmental Entomology, Guangdong Provincial Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China.
authors.forename: L-L
authors.initials: LL
authors.lastname: Zhang
authors.affiliation: Laboratory of Molecular and Developmental Entomology, Guangdong Provincial Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China.
authors.forename: B-J
authors.initials: BJ
authors.lastname: Zeng
authors.affiliation: Laboratory of Molecular and Developmental Entomology, Guangdong Provincial Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China.
authors.forename: S-C
authors.initials: SC
authors.lastname: Zheng
authors.affiliation: Laboratory of Molecular and Developmental Entomology, Guangdong Provincial Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China.
authors.forename: Q-L
authors.initials: QL
authors.lastname: Feng
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002784:Cholesterol / Q000494:pharmacology; D004441:Ecdysterone / Q000494:pharmacology; D008726:Methoprene / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation; D011401:Promoter Regions, Genetic; D050436:Regulatory Elements, Transcriptional; D018411:Spodoptera / Q000187:drug effects / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D002352:Carrier Proteins; C072087:sterol carrier proteins; D016718:Arachidonic Acid; D004441:Ecdysterone; D008726:Methoprene; D002784:Cholesterol
keywords: Spodoptera litura; cholesterol; promoter; sterol carrier protein; transcription factor