Esr1^tm2Ksk

Missense mutations (leucine to alanine) of the first two codons encoding hydrophobic residues were introduced in exon 9, which encodes the AF-2 motif. Previous in vitro studies showed that the disruption of these residues conferred insensitivity to estradiol. Sequence encoding a carboxy terminal histidine epitope tag was also added to allow for detection of the mutant protein. A floxed neo cassette that was inserted into the 3' untranslated region was excised from ES cells via expression of cre recombinase. RT-PCR analysis of RNA isolated from ES cells showed greater amounts of transcript after the expression of cre than prior to it, indicating that presence of neo affected mRNA stability. (J:75132)