Novel mouse strain with Cre recombinase in 11β-hydroxysteroid dehydrogenase-2-expressing cells

Abstract

Here we describe the generation and characterization of a mouse strain that expresses an improved Cre (iCre) recombinase ( 48 ) under the control of the endogenous 11β-hydroxysteroid dehydrogenase type 2 (11HSD2) promoter. Progeny of 11HSD2/iCre and ROSA26 reporter mice were used to determine the pattern of iCre expression by measuring the activity of the LacZ gene product β-galactosidase in a panel of tissues. On Cre recombinase activity, intense β-galactosidase activity (X-gal staining) was observed in the classic mineralocorticoid target segments of the kidney, as well as in the colon, and both female and male reproductive organs. Weaker iCre expression was detected in the lung and heart. In the brain, strong iCre activity was present in cardiovascular centers that are known to express 11HSD2 and mineralocorticoid receptors [nucleus tractus solitarius (NTS) and amygdala] as well as in the granular layer of the cerebellum. iCre expression was weaker in neonatal kidney and colon than in the adult but was present in the hair follicles and cartilage. These results indicate that in the 11HSD2/iCre strain iCre expression faithfully represents the expression pattern of endogenous 11HSD2. Thus this mouse model represents the first Cre deleter strain that can be used to eliminate desired genes in every mineralocorticoid target tissue. This mouse model should serve as a useful resource for investigators who want to study the function of genes involved in aldosterone action and genes in other pathways that are selectively expressed in these cells.

Aldosterone in the brain

“…3 and 4). In embryos and neonatal animals, subsequent investigators observed strong expression of HSD2 mRNA in a number of other sites (18,37,59,127,148). This widespread developmental pattern of HSD2 expression in the brain becomes restricted to just a few small populations of cells in adult rats (148,150) and, possibly, to just the NTS in mice (84,85).…”

“…The transitory nature of HSD2 expression in many parts of the brain became a source of confusion recently in the anatomic characterization of a transgenic mouse engineered to express Cre recombinase under the control of the HSD2 promoter (59,127). In HSD2-Cre mice crossed with a lacZ reporter strain, X-gal staining was used to visualize cells producing ␤-galactosidase (indicative of Cre-mediated recombination, either ongoing or earlier in their developmental lineage).…”

Hypertrophy in the Distal Convoluted Tubule of an 11β-Hydroxysteroid Dehydrogenase Type 2 Knockout Model

“…It is possible that 11bHSD2 expression was below the detection sensitivity of our immunofluorescence or PCR approaches, but others have reported similar findings. 36,41 This suggests that protection of MR by 11bHSD2 is less robust in the DCT than in the CNT and CCD, a concept with implications for corticosteroid signaling in these cells. Because the DCT expresses both the MR and glucocorticoid receptor, Na + transport is not likely to be regulated solely by the canonical aldosterone signaling pathways present in principal cells; glucocorticoids may exert a stronger influence here than in the CNT and CCD.…”

Mice lacking G0S2 are lean and cold-tolerant

“…Indicated organs were harvested and fixed in 4% paraformaldehyde (Electron Microscopy Sciences, 15713) on ice for 2 h and then cryoprotected in 30% sucrose at 4 °C (Schwarz Mann, 909530) overnight. 30 Tissues were then embedded in Tissue-Tek O.C.T. compound (Ted Pella, 27050) and cryosections were each made at a 10 μm thickness.…”