Characterization of melanocyte‐specific inducible Cre recombinase transgenic mice

Abstract

Conditional Cre-mediated recombination has emerged as a robust method of introducing somatic genetic alterations in an organ-specific manner in the mouse. Here, we generated and characterized mice harboring a 4-hydroxytamoxifen (OHT)-inducible Cre recombinase-estrogen receptor fusion transgene under the control of the melanocyte-specific tyrosinase promoter, designated Tyr::CreER(T2). Cre-mediated recombination was induced in melanocytes in a spatially and temporally controlled manner upon administration of OHT and was documented in embryonic melanoblasts, follicular bulb melanocytes, dermal dendritic melanocytes, epidermal melanocytes of tail skin, and in putative melanocyte stem cells located within the follicular bulge. Functional evidence suggestive of recombination in follicular melanocyte stem cells included the presence of Cre-mediated recombination in follicular bulb melanocytes 1 year after topical OHT administration, by which time several hair cycles have elapsed and the melanocytes residing in this location have undergone multiple rounds of apoptosis and replenishment. These Tyr:: CreER(T2) transgenic mice represent a useful resource for the evaluation of melanocyte developmental genetics, the characterization of melanocyte stem cell function and dynamics, and the construction of refined mouse models of malignant melanoma.

Truncating PREX2 mutations activate its GEF activity and alter gene expression regulation in NRAS-mutant melanoma

“…1A). We crossed these mice to Tyr-Cre ERT2 and Tyr-rtTA mice to express PREX2 E824 * only in melanocytes in response to doxycycline and Cre activation by tamoxifen (16,17). Subsequently, we crossed these mice into an established mouse model of melanoma, termed iNRAS (consisting of the alleles:…”

“…Transgenic founders were screened by PCR-based approach. TyrCreERT2 mice and the iNRAS mouse melanoma model have been described (16,18). Mice were interbred and kept on a FVB/C57Bl6 hybrid background in specific pathogen free environment at MD Anderson Cancer Center mouse facility.…”

The epigenetic modifier EZH2 controls melanoma growth and metastasis through silencing of distinct tumour suppressors

“…Tyr::N-Ras Q61K animals and Ink4a-defficient mice have previously been described 14,34,61 . The Tyr::Cre ERT2 line 14,31,39 , Ezh2 lox animals 19,21 and R26R::LacZ mice 40 have been analyzed elsewhere. Mouse genotyping was performed according to a standard DNA isolation protocol 62 , followed by PCR using a Taq PCR Core Kit (201225, Qiagen) and primers indicated in (Supplementary Table 4).…”

“…Because EZH2 was highly expressed in human and murine melanoma and linked to poor patient survival, we studied its function in vivo. To this end, mice carrying floxed alleles of the Ezh2 locus 19 were used to conditionally delete Ezh2 in the melanocytic lineage by tamoxifen (TM)-induced activation of Cre-recombinase (Tyr::Cre ERT2 ) 39 . Inclusion of a Cre-reporter allele (R26R::LacZ) 40 allowed fate mapping of recombined cells in vivo.…”

Temporal control of neural crest lineage generation by Wnt/β-catenin signaling

“…Embryos carrying one allele for lineage tracing are indicated as R26R or Z/EG. The following Cre lines were used: Wnt1-Cre (Danielian et al, 1998), Sox10-Cre (Matsuoka et al, 2005), Dhh-Cre (Jaegle et al, 2003;Joseph et al, 2004), Plp-CreERT2 (Leone et al, 2003) and Tyr-CreERT2 (Bosenberg et al, 2006). Genotyping for all Cre alleles was performed by PCR with primers Cre-up (5Ј-ACCAGGTTCGTTCACTCATGG-3Ј) and Cre-lo (5Ј-AGGCTAAGTGCCTTCTCTACAC-3Ј) and 35 cycles of 94°C for 45 seconds, 58°C for 30 seconds and 72°C for 1 minute, to amplify a 217 bp fragment within the Cre ORF.…”