Estradiol-induced gene expression in largemouth bass (Micropterus salmoides).
Vitellogenin (Vtg) and estrogen receptor (ER) gene expression levels were measured in largemouth bass to evaluate the activation of the ER-mediated pathway by estradiol (E(2)). Single injections of E(2) ranging from 0.0005 to 5 mg/kg up-regulated plasma Vtg in a dose-dependent manner. Vtg and ER mRNAs were measured using partial cDNA sequences corresponding to the C-terminal domain for Vtg and the ligand-binding domain of ER alpha sequences. After acute E(2)-exposures (2 mg/kg), Vtg and ER mRNAs and plasma Vtg levels peaked after 2 days. The rate of ER mRNA accumulation peaked 36-42 h earlier than Vtg mRNA. The expression window for ER defines the primary response to E(2) in largemouth bass and that for Vtg a delayed primary response. The specific effect of E(2) on other estrogen-regulated genes was tested during these same time windows using differential display RT-PCR. Specific up-regulated genes that are expressed in the same time window as Vtg were ERp72 (a membrane-bound disulfide isomerase) and a gene with homology to an expressed gene identified in zebrafish. Genes that were expressed in a pattern that mimics the ER include the gene for zona radiata protein ZP2, and a gene with homology to an expressed gene found in winter flounder. One gene for fibrinogen gamma was down-regulated and an unidentified gene was transiently up-regulated after 12 h of exposure and returned to basal levels by 48 h. Taken together these studies indicate that the acute molecular response to E(2) involves a complex network of responses over time.
Bowman
Christopher J
CJ
Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, USA.
Kroll
Kevin J
KJ
Gross
Timothy G
TG
Denslow
Nancy D
ND
D000595:Amino Acid Sequence; D000818:Animals; D001492:Bass / Q000235:genetics / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D047628:Estrogen Receptor alpha; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D007700:Kinetics; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis / Q000187:drug effects; D011960:Receptors, Estrogen / Q000235:genetics; D016415:Sequence Alignment; D014819:Vitellogenins / Q000097:blood / Q000235:genetics
D047628:Estrogen Receptor alpha; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D014819:Vitellogenins; D004958:Estradiol