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Generation and characterization of Ins1-cre-driver C57BL/6N for exclusive pancreatic beta cell-specific Cre-loxP recombination.

Authors: Yoshikazu Y. Hasegawa, Yoko Y. Daitoku, Seiya S. Mizuno, Yoko Y. Tanimoto, Saori S. Mizuno-Iijima, Miki M. Matsuo, Noriko N. Kajiwara, Masatsugu M. Ema, Hisashi H. Oishi, Yoshihiro Y. Miwa, Kazuyuki K. Mekada, Atsushi A. Yoshiki, Satoru S. Takahashi, Fumihiro F. Sugiyama, Ken-ichi K. Yagami
Published: 04/28/2014, Experimental animals / Japanese Association for Laboratory Animal Science


Cre/loxP system-mediated site-specific recombination is utilized to study gene function in vivo. Successful conditional knockout of genes of interest is dependent on the availability of Cre-driver mice. We produced and characterized pancreatic β cell-specific Cre-driver mice for use in diabetes mellitus research. The gene encoding Cre was inserted into the second exon of mouse Ins1 in a bacterial artificial chromosome (BAC). Five founder mice were produced by microinjection of linearized BAC Ins1-cre. The transgene was integrated between Mafa and the telomere on chromosome 15 in one of the founders, BAC Ins1-cre25. To investigate Cre-loxP recombination, BAC Ins1-cre25 males were crossed with two different Cre-reporters, R26R and R26GRR females. On gross observation, reporter signal after Cre-loxP recombination was detected exclusively in the adult pancreatic islets in both F1 mice. Immunohistological analysis indicated that Cre-loxP recombination-mediated reporter signal was colocalized with insulin in pancreatic islet cells of both F1 mice, but not with glucagon. Moreover, Cre-loxP recombination signal was already observed in the pancreatic islets at E13.5 in both F1 fetuses. Finally, we investigated ectopic Cre-loxP recombination for Ins1, because the ortholog Ins2 is also expressed in the brain, in addition to the pancreas. However, there was no Cre-loxP recombination-mediated reporter signal in the brain of both F1 mice. Our data suggest that BAC Ins1-cre25 mice are a useful Cre-driver C57BL/6N for pancreatic β cell-specific Cre-loxP recombination, except for crossing with knock-in mice carrying floxed gene on chromosome 15.