[en] The homeobox factor PDX-1 is a key regulator of pancreatic morphogenesis and glucose homeostasis; targeted disruption of the PDX-1 gene leads to pancreatic agenesis in pdx-1(-/-) homozygotes. Pdx-1 heterozygotes develop normally, but they display glucose intolerance in adulthood. Like certain other homeobox proteins, PDX-1 contains a consensus FPWMK motif that promotes heterodimer formation with the ubiquitous homeodomain protein PBX. To evaluate the importance of PDX-1:PBX complexes in pancreatic morphogenesis and glucose homeostasis, we expressed either wild-type or PBX interaction defective PDX-1 transgenes under control of the PDX-1 promoter. Both wild-type and mutant PDX-1 transgenes corrected glucose intolerance in pdx-1 heterozygotes. The wild-type PDX-1 transgene rescued the development of all pancreatic lineages in pdx-1(-/-) animals, and these mice survived to adulthood. In contrast, pancreata from pdx-1(-/-) mice expressing the mutant PDX-1 transgene were hypoplastic, and these mice died within 3 weeks of birth from pancreatic insufficiency. All pancreatic cell types were observed in pdx-1(-/-) mice expressing the mutant PDX-1 transgene; but the islets were smaller, and increased numbers of islet hormone-positive cells were noted within the ductal epithelium. These results indicate that PDX-1:PBX complexes are dispensable for glucose homeostasis and for differentiation of stem cells into ductal, endocrine, and acinar lineages; but they are essential for expansion of these populations during development.
Disciplines :
Biochemistry, biophysics & molecular biology
Author, co-author :
Dutta, S.
Gannon, M.
Peers, Bernard ; Université de Liège - ULiège > Département des sciences de la vie > GIGA-R : Biologie et génétique moléculaire
Wright, C.
Bonner-Weir, S.
Montminy, M.
Language :
English
Title :
PDX:PBX complexes are required for normal proliferation of pancreatic cells during development.
Publication date :
2001
Journal title :
Proceedings of the National Academy of Sciences of the United States of America
ISSN :
0027-8424
eISSN :
1091-6490
Publisher :
National Academy of Sciences, Washington, United States - District of Columbia