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. Author manuscript; available in PMC: 2009 Nov 1.
Published in final edited form as: Nat Genet. 2009 Mar 12;41(5):544–552. doi: 10.1038/ng.356

Figure 1. Benign hyperplasias induced by melanocyte specific expression of BRafV600E.

Figure 1

(a) Mice carrying various conditional alleles of BRaf (BRafCA) and/or Pten (Ptenlox4-5 or Ptenlox5) were crossed to Tyr::CreER mice with melanocyte specific expression of a hormone dependent form of Cre recombinase (CreERT2) 17,20. 4-HT dependent activation of CreER leads to melanocyte specific conversion of BRafCA→BRafV600E and the conversion of the Ptenlox alleles to null alleles.

BRafCA/+ (b), Tyr::CreER; BRafCA/+ (c) and Tyr::CreER; BRafCA/CA (d) mice were treated topically with 4-HT and monitored for 75 weeks for signs of melanocytic proliferation (i). Mice were euthanized and skin from the ear (ii, iii) and flank (iv) was stained with hematoxylin and eosin and inspected for the presence of pigmented cells. (e) A Tyr::CreER; BRafCA/+ mouse developed a papular pigmented lesion ∼60 weeks after topical administration of 4-HT (i). This mouse was euthanized and skin sections encompassing the lesion were stained with hematoxylin and eosin and inspected for the presence of pigmented cells (ii & iii).