Tg(Myh6*/tetO-GCaMP2)1Mik

This transgene contains a calcium-sensing molecule, GCaMP2, under the transcriptional control of a minimally active mouse alpha myosin heavy chain promoter fused to seven copies of the tetracycline-responsive promoter element (tetO). GCaMP2 consists of circularly permutated eGFP with the molecule interrupted at residue 145 and a 13-residue peptide of myosin light chain kinase (M13) and calmodulin (CaM), placed at the new N and C termini, respectively. An RSET polyHis peptide was introduced N-terminal to the original methionine in GCaMP1. Mutations resulting in increased brightness (D180Y and V93I), thermal stability (V163A, and S175G) and to prevent GFP dimerization (A206K) were introduced. GCaMP2 is 200 times brighter than GCaMP1. Three GATA sites and two thyroid-like response elements are ablated in Myh6 to make the promoter minimally active. When bred with transgenic mice expressing a tetracycline transactivator or reverse transactivator protein, cardiac-specific expression of GCaMP2 can be controlled by withdrawal or administration of a tetracycline analog. (J:107637)