Female ticks require a blood meal for vitellogenesis to occur. Vitellogenin (Vg), a precursor of yolk protein, is essential for egg development and Vg synthesis appears to be regulated by ecdysteroids in ticks. To better understand the regulation of Vg synthesis in ticks, the Vg gene was identified from Orinthodoros moubata. OmVg is composed of 5,502 bp encoding a 1,834 aa protein with Vg specific characteristics. OmVg gene showed the highest homology with the hard tick Dermacentor variabilis and was included in the same clade of a phylogenetic tree as the hard tick and crustacean Vg genes. OmVg gene expression was observed in females but not in nymphal stages and during molting. Both mated and virgin females showed OmVg expression approximately 3 days after engorgement. However, as time passed, mated females showed significant increases in OmVg expression whereas virgin females didn’t. OmVg expression is thought to be regulated by ecdysteroids functioning through a complex with an ecdysteroid receptor (EcR) and retinoid X receptor (RXR). EcR and RXR expression increased in both mated and virgin females soon after engorgement. However, ecdysteroid titer only increased in mated females indicating a high titer of ecdysteroids in mated females up-regulates OmVg expression. The OmVg gene was expressed in the fat body and midgut of O. moubata. Further studies are underway to determine other factors that may explain differences between mated and virgin O. moubata females. Understanding the regulation of reproduction in ticks may lead to the development of better mechanisms for controlling ticks and preventing the spread of tick vectored diseases.

To develop a biomarker for the monitoring of the contamination of estrogenic endocrine disrupters in the aquatic environment, reverse transcription -polymerase chain reaction (RT-PCR) analysis of vitellogenin (Vg) mRNA expression was optimized in Bombina

In an effort to develop the tools for monitoring the contamination of xenoestrogen in the aquatic environment of Korea, reverse transcription-polymerase chain reaction (RT-PCR) analysis of vitellogenin (VTG) mRNA expression were optimized in Synechogobius

Gene expressions of cytochrome P4501A (CYP1A), aryl hydrocarbon receptor (AhR) and vitellogenin (Vg) by endocrine disruptors, benzo[]pyrene (B[a]P) and tributyltin (TBT) were examined in cultured eel hepatocytes which were isolated from eels treated previously with B[a]P (10 mg/kg) or estradiol- (20 mg/kg) in vivo, and the relationship between CYP1A, AhR and Vg genes were studied. When the cultured eel hepatocytes were treated with B[a]P () the gene expressions of CYP1A and AhR were enhanced in a concentration-dependent manner. However, when treated with TBT () the gene expressions of CYP1A and AhR were suppressed at high concentrations (), while having no effects at low concentrations (). Gene expression of Vg was also suppressed by TBT in a concentration-dependent manner in cultured eel hepatocytes which was previously treated in vivo with estradiol-.

Vg은 난생 척추동물의 성숙한 암컷 혈청에 존재하는 성 특이 단백질로서 에 의해 합성이 유도된다. 본 연구는 뱀장어 Vg과 ER 유전자 발현에 대한 androgen과 성장호르몬(GH)의 영향을 조사하였다. 미성숙 뱀장어()에 , 뱀장어 recombinant GH(eGH, ) 또는 methyltestosterone(MT, )를 각각 단독 또는 eGH 또는 MT와 혼합하여 주사한 후 10일 후에 샘플을 채취하였다. 간 ER과 Vg mRNA는 RT-PCR을