Conditional inactivation of Myc impairs development of the exocrine pancreas.
Recent studies have shown that Wnt/beta-catenin signaling is essential for development of the exocrine pancreas, but the role of beta-catenin-dependent target genes such as Myc during pancreatic development is not well known. Here, we show that tissue-specific deletion of Myc causes a slightly accelerated differentiation of pancreatic epithelial cells into endocrine cells and perturbs the proliferation of pancreatic progenitors and acinar precursor cells during early development, resulting in a severe reduction of the epithelial cell mass of pancreatic buds and an extensive acinar hypoplasia. Loss of Myc does not affect the expression of the tissue-specific transcription factor PTF1a, which is required for the differentiation of acinar cells. In contrast to its role for exocrine cell growth, the development of endocrine cell lineages is not significantly disturbed. These data suggest that Myc is required for the expansion of the exocrine pancreas. Our observations are consistent with the findings in beta-catenin-deficient pancreas, suggesting that Wnt/beta-catenin signaling affects the proliferation of pancreatic epithelial cells and acinar precursors through its target gene Myc.
Nakhai
Hassan
H
Department of Internal Medicine, Technical University of Munich, Munich, Germany.
Siveke
Jens T
JT
Mendoza-Torres
Lidia
L
Schmid
Roland M
RM
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D049109:Cell Proliferation; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D016259:Genes, myc; D007515:Islets of Langerhans / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009928:Organ Specificity; D046790:Pancreas, Exocrine / Q000166:cytology / Q000196:embryology* / Q000378:metabolism*; D011247:Pregnancy; D016271:Proto-Oncogene Proteins c-myc / Q000172:deficiency / Q000235:genetics; D015398:Signal Transduction; D051153:Wnt Proteins / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
C495267:CTNNB1 protein, mouse; C489428:Myc protein, mouse; D016271:Proto-Oncogene Proteins c-myc; D051153:Wnt Proteins; D051176:beta Catenin