Yue-wern Huang, Ph.D.
Post-Doctoral Fellow

Current contact information
Yue-wern Huang, Ph.D.
Assistant Professor
Department of Biological Sciences
University of Missouri-Rolla
105 Schrenk Hall
1870 Miner Circle
Rolla, MO 65409-1120

Tel: 573-341-6589
Fax: 573-341-4821
E-mail: huangy@umr.edu MSU E-mail: huangyu@pilot.msu.edu
http://www.umr.edu/~huangy

Education
Postdoctoral Fellow, Department of Biochemistry, Michigan State University, Sept., 1998 to present.
PhD, University of Wisconsin-Madison. August 1998.
MSc, Graduate Institute of Biology, National Taiwan Normal University. June 1986-June 1988

Research Project

It has been hypothesized that some chemicals can mimic the activities of endogenous estrogen, and therefore may adversely affect human and wildlife reproductive fitness. This is commonly referred to as endocrine disruption, which has been defined as alterations of the structure or function(s) of the endocrine system caused by exogenous chemical substance or mixtures. Endocrine disrupters include a variety of structurally diverse substances such as natural products, pesticides, phytoestrogens, pharmaceuticals, and industrial chemicals. The objectives of my postdoctoral research are to elucidate mechanisms of endocrine disruption in amphibians, as well as to test and screen the estrogenic potency of alleged environmental estrogen mimics using in vitro and in vivo models.

Three complementary assays are employed:

  1. competitive binding of chemicals to a glutathione-S-transferase (GST) fusion Xenopus estrogen receptor (ER) protein,
  2. chimeric estrogen receptor/reporter gene expression assay, and
  3. in vivo studies using RT-PCR to measure vitellogenin mRNA as a biomarker for exposure to xenoestrogens.
The competitive binding assay uses a bacterially expressed fusion protein consisting of GST and the ER ligand binding domain (LBD) of Xenopus laevis. The GST-xERdef fusion protein is partially purified to greater than 90% purity and subsequently used in a semi-high throughput competitive binding assay to examine the ability of potential endocrine disrupters to compete with 17b-estradiol (E2) for binding to the recombinant ER protein.

The effect of potential endocrine disrupters on in vitro gene expression is then assessed using a chimeric receptor/reporter gene assays. The chimeric receptor consists of the LBD from Xenopus linked to the DNA binding domain (DBD) of Gal4, a yeast transcription factor. The chimeric receptor is then transiently transfected with a Gal4-regulated luciferase reporter gene into MCF-7 human breast cancer cells. The induction of the reporter gene is an estimate of estrogenic potency of the chemical interested. In addition, I am currently investigating the use of two Xenopus cell lines so that the gene expression data would be more relevant to amphibian species.

Potential endocrine disrupters are also being investigated in vivo for their ability to induce the expression of vitellogenin, a precursor molecule for yolk proteins, that is a biomarker for exposure to estrogenic chemicals. Xenopus laevis will be treated with potential endocrine disrupters and vitellogenin mRNA will be measured using a quantitative, competitive reverse transcription-polymerase chain reaction (RT-PCR) and possibly an enzyme-linked immunosorbent assay (ELISA). In addition to identifying and assessing chemicals for estrogenic activity in an amphibian model, results from these studies will also indicate the ability of an inexpensive in vitro assay to predict responses in vivo.