pSGB4SH was digested with NotI to release the β4/β-gal transgene (Fig. 1B). Following agarose gel electrophoresis, the transgene fragment was excised and the DNA was extracted from the gel using a QIAquick Gel Extraction Kit (QIAGEN, California, USA). The purified DNA was injected into pronuclei followed by implantation into pseudopregnant females. The C57BL/6 × SJL F2 hybrid mouse strain was used for all transgenic experiments. Injection of DNA and all subsequent steps up to and including the generation of founder animals were performed by the University of Massachusetts Medical School Transgenic Animal Modeling Core. Transgenic founders were identified by polymerase chain reaction. Founders were mated with C57BL/6 × SJL F2 hybrid mice to establish transgenic lines. Adequate measures were taken to minimize pain and discomfort to the animals. All procedures were conducted in accordance with the rules of the Institutional Animal Care and Use Committee of the University of Massachusetts Medical School.
