A doxycycline-inducible, tissue-specific aromatase-expressing transgenic mouse

Area of Science:

• Biochemistry
• Endocrinology
• Genetics

Background:

• Aromatase, an enzyme converting androgens to estrogens, is present in both reproductive and non-reproductive tissues.
• Low circulating estrogen levels in males suggest local estrogen production is crucial for physiological functions and disease development.
• Paracrine and intracrine actions of locally produced estrogens are hypothesized to be significant.

Purpose of the Study:

• To develop a tissue-specific, doxycycline-inducible transgenic mouse model for investigating the role of local estrogen production.
• To validate the functionality of the developed transgenic system in vitro and in vivo.

Main Methods:

• Constructed a transgene (pTetOAROM) with human aromatase cDNA (hAROM) and luciferase under a tetracycline-responsive promoter.
• Validated transgene induction in MBA-MB-231tet cells with doxycycline, confirming increased hAROM and luciferase expression/activity.
• Generated pTetOAROM founder mice and bred them with MMTVrtTA mice to create double-transgenic models for tissue-specific expression.

Main Results:

• Doxycycline treatment in vitro significantly increased hAROM transcript (17-fold) and aromatase activity (26-fold).
• Double-transgenic mice exhibited doxycycline-induced human aromatase expression in mammary, salivary glands, and seminal vesicles.
• Bioluminescence imaging and RT-PCR confirmed transgene expression and activity in targeted tissues.

Conclusions:

• Successfully generated a transgenic mouse model with temporal and spatial control over human aromatase expression.
• This model is a valuable tool for studying the physiological significance of local estrogen production.
• Facilitates research into estrogen's role in metabolism, cancer, and other conditions regulated by paracrine/intracrine signaling.