Expression of tamoxifen‐inducible CRE recombinase in Lcn5‐CreERT2 transgenic mouse caput epididymis

SUMMARY The epididymis, which connects the testis to vas deferens, plays a crucial role regulating sperm maturation and fertilization. Here, a tamoxifen‐inducible CreER T2 recombinase transgenic mouse was generated to study the function of genes in the caput epididymis using the Cre/LoxP system, which is driven by the 1.8‐kb Lcn5 promoter ( Lcn5‐CreER T2 ). Both CRE recombinase and ER T2 mRNA were specifically expressed in the caput epididymis, beginning at postnatal Day 30 and increasing thereafter. Crossing these Lcn5‐CreER T2 transgenic mice with Rosa26; mT/mG reporter mice, which express membrane‐bound GFP (mGFP) only after CRE is active at its genetic locus, resulted in the presence of GFP only in the middle/distal caput epididymis after tamoxifen induction. Efficiency of the CRE recombinase production in the caput epididymis was dose‐ and time‐dependent. These tamoxifen‐inducible caput epididymis‐specific CRE recombinase transgenic mice thus provides a simple approach to modulate epididymal principal cells in vivo, allowing for the genetic investigation of caput epididymis‐specific gene functions during sperm maturation. 84: 257–264, 2017. © 2016 Wiley Periodicals, Inc .