title: Expression of pancreatic and duodenal homeobox1 (PDX1) protein in the interior and exterior regions of the intestine, revealed by development and analysis of Pdx1 knockout mice.
abstract: We developed pancreatic and duodenal homeobox1 (Pdx1) knockout mice to improve a compensatory hyperinsulinemia, which was induced by hyperplasia in the β cells or Langerhans' islands, as the diabetic model mice. For targeting of Pdx1 gene by homologous recombination, ES cells derived from a 129(+Ter) /SvJcl×C57BL/6JJcl hybrid mouse were electroporated and subjected to positive-negative selection with hygromycin B and ganciclovir. As these results, one of the three chimeric mice succeeded to produce the next or F1 generation. Then, the mouse fetuses were extracted from the mother's uterus and analyzed immunohistologically for the existence of a pancreas. The fetuses were analyzed at embryonic day 14.5 (E14.5) because Pdx1 knockout could not alive after birth in this study. Immunohistochemical staining revealed that 10 fetuses out of 26 did not have any PDX1 positive primordium of the pancreas and that the PDX1 expresses in both the interior and exterior regions of intestine. In particular, one the exterior of the intestine PDX1 was expressed in glands that would be expected to form the pancreas. The result of PCR genotyping with extracted DNA from the paraffin sections showed existence of 10 Pdx1-knockout mice and corresponded to results of immunostaining. Thus, we succeeded to establish a Pdx1-knockout (Pdx1 (-/-)) mice.
authors.affiliation: Central Institute for Experimental Animals, Kawasaki-shi, Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Hashimoto
authors.affiliation: Central Institute for Experimental Animals, Kawasaki-shi, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kamisako
authors.affiliation: Central Institute for Experimental Animals, Kawasaki-shi, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kagawa
authors.affiliation: National Agriculture and Food Research Organization, Institute of Livestock and Grassland Science, Tsukuba, Japan.
authors.forename: Seiki
authors.initials: S
authors.lastname: Haraguchi
authors.affiliation: Central Institute for Experimental Animals, Kawasaki-shi, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Yagoto
authors.affiliation: Central Institute for Experimental Animals, Kawasaki-shi, Japan.
authors.forename: Ri-Ichi
authors.initials: R
authors.lastname: Takahashi
authors.affiliation: Central Institute for Experimental Animals, Kawasaki-shi, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawai
authors.affiliation: Central Institute for Experimental Animals, Kawasaki-shi, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suemizu
keywords: Pdx1 gene; knockout mice; pancreas