Gt(ROSA)26Sor^{tm1(CAG-MCPySTco)Cvp}

Merkel cell polyomavirus (MCPyV), a close relative of simian vacuolating 40 (SV40) virus, is clonally integrated into the tumor genome in ~80% of Merkel cell carcinomas (MCC); MCC is a highly aggressive non-melanoma skin cancer. The knocked-in sequence of this allele contains the CAG promoter - which consists of the cytomegalovirus immediate early (CMV-EI) enhancer followed by a 1.3-kb DNA segment including the promoter, first exon and first intron of the chicken beta-actin gene, with the 3' splice junction sequence replaced by that of the rabbit hemoglobin beta gene - followed by a loxP-flanked STOP/Pgk-neomycin phosphotransferase (neo) cassette and a codon-optimized cDNA encoding the small T antigen of MCPyV (MCPySTco; also called MCPyV_gp4, protein sequence YP_009111422.1) with the human growth hormone polyadenylation signal. Upon tissue-specific Cre recombinase excision of the STOP/neo cassette, expression of the small T antigen is driven by the CAG promoter. (J:243752)