Vitellogenin Gene Transcription: A Relative Quantitative Exposure Indicator of Environmental Estrogens

Abstract

We report the development of a quantifiable exposure indicator for measuring the presence of environmental estrogens in aquatic systems. Synthetic oligonucleotides, designed specifically for the vitellogenin gene (Vg) transcription product, were used in a reverse transcription-polymerase chain reaction (RT-PCR) protocol. This extremely sensitive and rapid method was able to detect vitellogenin gene transcription in male common carp (Cyprinus carpio) injected with 17beta-estradiol. Sequence analysis of the induced mRNA product confirmed a vitellogenin gene transcript with homology to rainbow trout and fathead minnow vitellogenin cDNA sequences. Relative levels of vitellogenin gene induction among individuals were quantified by incorporating 18S ribosomal RNA universal primers and Competimers in a PCR multiplex reaction with primers for vitellogenin. This method is more sensitive than current protocols, such as mortality, visible signs of stress, or other techniques that look for unscheduled gene expression, because it measures the appearance of primary transcripts at the nanogram level. In addition, this procedure does not sacrifice accuracy or reliability, even though the exposure to estrogen is within 1 d. This research will support the construction of regional stressor profiles, thereby providing a method for comparative environmental exposure assessment. It may also provide an in vivo screening method for potential endocrine-disrupting compounds.

Effects of xenoestrogens on the expression of vitellogenin (vtg) and cytochrome P450 aromatase (cyp19aandb) genes in zebrafish (Danio rerio) larvae

“…[24,25] In this study, the effects of exposure to E2 (0-100 µg/L) on the kinetics of the expression of 3 genes in the early development of zebrafish were investigated by RT-PCR. Expression of vtg was induced as early as 4 dpf at E2 concentrations of 1 µg/L and higher.…”

Biomarkers for exposure to estrogenic compounds: Gene expression analysis in zebrafish (Danio rerio)

“…Many studies have shown that male organisms of egg-laying vertebrates, exposed to estrogenic compounds, synthesize this protein in substantial amounts in contrast to unexposed controls (Lim et al, 1991;Bowman et al, 2000;Funkenstein et al, 2000;Lattier et al, 2001;Rey et al, 2005). This marker is frequently used in assays designed to indicate the endocrine potential of a sample.…”

Assessment of reproductive stress in natural populations of the fish Aphanius fasciatus using quantitative mRNA markers

“…VgA mRNA showed very low and similar levels in both sexes, reflecting its almost exclusively hepatic synthesis in Cyprinodonta (Fig. 3, see below) (Lattier et al 2001, García-Reyero et al 2004). In contrast, MTA and MTB mRNA did show significant variation among populations.…”