Transgenic Cre expression mice for generation of erythroid‐specific gene alterations

Summary: Transgenic mice that express Cre recombinase in erythroid cell lineages were developed so that genes affecting erythropoiesis/hematopoiesis may be altered without necessarily affecting fetus viability. A micro-LCR cassette-β-globin promoter-Cre recombinase gene (μLCR-βpr-Cre) construct was synthesized and used to generate transgenic mice. Concurrently, we produced mice containing a μLCR-loxP-flanked β sickle gene (μLCR-loxP-βS-loxP) construct. μLCR-βpr-Cre mice with intact transgenes in variable copy number were identified. Cre expression was assessed by RNAse protection and RT-PCR. Cre function was ascertained by breeding to μLCR-loxP-βS-loxP mice. We demonstrate that βS expression was not detected in the blood of bigenics, but the gene was present in nonerythroid cells. Thus, excision of the loxP-flanked βS gene was restricted to erythroid cell lineages. genesis 39:1–9, 2004. © 2004 Wiley-Liss, Inc.