Tg(Hsd17b1-icre/ERT2)3Casa

A 200kb BAC containing the Hsd17b1 gene was modified by homologous recombination to generate the construct. The open reading frame sequence for codon-improved cre recombinase (icre) fused to a mutated ligand-binding domain (LBD) of the human estrogen receptor (ERT2) was inserted into the exon containing the transcription initiation codon of the Hsd17b1 gene. The initial targeting vector also contained the bovine growth hormone polyA signal and an Frt-flanked ampicillin cassette. The amp marker was subsequently removed from targeted by clones upon electroporation of a plasmid expressing Flp recombinase. Purified BAC clones were injected into (C57BL/6 x CBA)F1 oocytes. Three lines expressing the transgene were generated. Lines 1 and 2 were shown to contain 2 copies of the insert by Southern blot, while line 3 had 8 copies. Line 3 mRNA levels of icre/ERT2 were highest in ovaries and this line was used for subsequent analyses. (J:170001)