Gcg^tm2.1Rsy

A Lox-flanked transcriptional blocking cassette consisting of a splice acceptor (SA), an internal ribosomal entry site (IRES), and an EGFP gene with a poly(A) signal (pA) was inserted into the intron between exons 2 and 3. In the absence of Cre recombinase, expression of the targeted allele is suppressed generating a null allele. A neomycin resistance cassette was removed by Flp-mediated recombination in the germline. (J:251956)