Multiple elements and protein factors coordinate the basal and cyclic adenosine 3',5'-monophosphate-induced transcription of the lutropin receptor gene in rat granulosa cells.
The expression of the lutropin receptor (LHR) in granulosa cells is a complex phenomenon under the hormonal control of FSH and estradiol. Using primary cultures of granulosa cells from immature female rats pretreated with diethylstilbestrol (a compound with estrogen-like activity), the role of FSH in LHR induction was studied. Previous studies from our laboratory have shown that FSH or 8-bromo-cAMP addition to these cells causes a marked increase in the rate of transcription of the rat LHR (rLHR) gene. The present studies were undertaken to compare the properties of the rLHR gene in undifferentiated vs. differentiated rat granulosa cells as a means of determining those elements that confer basal activity and cAMP responsiveness. Our studies show that the proximal 155 bp (relative to the translational initiation codon) of the 5'-flanking region of rLHR gene represent a minimal promoter that accounts for the basal expression of this receptor in rat granulosa cells. A major domain located between nucleotides (nt) -90 and -120, with another one possibly being between nt -120 and -155, induced activation of basal transcriptional activity. An inhibitory domain was observed to lie between nt -186 and -1375. Our data further show that multiple elements within the 2.1 kb of the 5'-flanking region of the rLHR gene are involved in the 8-bromo-cAMP-induced expression of the LHR gene. Of these, the three Sp1-binding sites within the proximal portion of the 5'-flanking region appear to be important for both basal as well as cAMP-induced rLHR gene transcription.
Chen
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Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa City 52242, USA.
Shi
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Liu
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Segaloff
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D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005260:Female; D051717:Fushi Tarazu Transcription Factors; D005786:Gene Expression Regulation; D006107:Granulosa Cells / Q000378:metabolism*; D018398:Homeodomain Proteins; D016296:Mutagenesis; D009687:Nuclear Proteins / Q000378:metabolism; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear; D011974:Receptors, LH / Q000235:genetics*; D016329:Sp1 Transcription Factor / Q000378:metabolism; D054339:Steroidogenic Factor 1; D050656:Transcription Factor AP-2; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects*; D014162:Transfection
D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011974:Receptors, LH; D016329:Sp1 Transcription Factor; D054339:Steroidogenic Factor 1; D050656:Transcription Factor AP-2; D014157:Transcription Factors; D004247:DNA; D000242:Cyclic AMP