Conditional and inducible gene targeting using Cre/loxP-mediated recombination is a powerful
reverse genetics approach used to study spatiotemporal gene functions in specified cell types. To enable
temporal gene manipulation in the melanocyte lineage, we established a novel inducible Cre-driver mouse
line by targeting an all-in-one tetracycline/doxycycline (Dox)-inducible Cre expression cassette into the
Pmel locus (PmelP2A-TetON3G-TRE3G-iCre), a gene locus preferentially expressed in pigment cells. By
crossing these Cre-driver mice with a strong Cre-reporter mouse line, Gt(ROSA)26Sortm9(CAGtdTomato)Hze, we show the effectiveness of the PmelP2A-TetON3G-TRE3G-iCre mouse line in facilitating
Dox-inducible Cre/loxP recombination in a wide variety of pigment cell lineages including hair follicle
melanocytes and their stem cells. Furthermore, to demonstrate proof of concept, we ablated Notch signaling
postnatally in the PmelP2A-TetON3G-TRE3G-iCre mice. In agreement with the previously reported
phenotype, induced ablation of Notch signaling in the melanocyte lineage resulted in premature hair graying,
demonstrating the utility of the PmelP2A-TetON3G-TRE3G-iCre allele. Therefore, the PmelP2A-TetON3GTRE3G-iCre mouse line is suitable for assessing gene functions in melanocytes using an in vivo inducible
reverse genetics approach. Furthermore, we unexpectedly identified previously unrecognized PMELexpressing cells in non-pigmentary organs in the mice, suggesting unanticipated functions of PMEL other
than melanosome formation. |
