LoxP sites flank exons 3-5 of the Calcineurin β1 (Ppp3r1, protein phosphatase 3, regulatory subunit B, alpha isoform (calcineurin B, type I)) gene in these floxed mutant mice. When bred to Cre-recombinase mice, excision of the floxed exons can be directed in a tissue/cell-specific manner in the resulting offspring. Disruption of the calcineurin β1 subunit results in a lack of calcineurin enzymatic activity in non-germline cell types.
Ppp3r1 is a Ca2+-binding regulatory subunit of heterodimeric calcineurin, a Ca2+- and calmodulin-dependent serine/threonine protein phosphatase involved in a number of cellular processes and calcium-dependent signaling pathways.
When crossed with Lck-cre mice to specifically block calcineurin expression in thymocytes, it was shown that calcineurin β1 is essential for positive but not negative selection during thymocyte development.
When bred to a strain expressing Cre recombinase in endothelial cells (see Stock No. 008863 for example), this mutant mouse strain may be useful in studies of angiogenesis.
